LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


Class 


LEATHER  MANUFACTURE 

A   PRACTICAL  HANDBOOK 

\ 

TANNING,   CURRYING,   AND   CHROME 
LEATHER  DRESSING 


BY   ALEXANDER    WATT 

•   • 
AUTHOR   OF  "1HB  AKT  Of  POAP-MAUXO,"   "  WJECTROOIRTA1J.CRGT,"   ETC.,  «TC. 


t'lFTU  EDITION,   THOROUGHLY  REVISED  AXD  ENLARGED 


NEW  YORK 

D.  VAN   NOSTRAND   COMPANY 

23  MURRAY  A>D  27  WARREN  STREETS 

LONDON 

CROSBY    LOCKWOOD    AND    SON 

1906 


PREFACE. 


THE  AUTIIOH  deems  it  advisable,  in  explanation  of  the 
appearance  of  the  present  volume,  to  mention  that,  not- 
withstanding diligent  inquiry,  he  was  unsuccessful  in 
meeting  with  an  English  work  on  the  subjects  com- 
prised therein.  It  is  true  there  are  articles  upon  Leather 
Manufacture  in  our  various  scientific  cyclopaedias  and 
technical  journals,  but  to  the  Author's  mind  it  appeared 
strange  that  so  important  an  art  should  be  unrepre- 
sented by  a  special  work  upon  the  subject  in  this 
country,  while  other  countries,  especially  France,  Ger- 
many, and  Austria,  have  provided  numerous  books  upon 
the  various  branches  of  the  trade. 

It  therefore  seemed  to  the  Author  that  a  carefully  pre- 
pared Handbook,  embodying  all  the  information  he  could 
gather  which  seemed  likely  to  be  useful  to  the  various 
trades  concerned,  and  including  recent  processes  and  im- 
provements, could  not  fail  to  prove  widely  acceptable  to 
manufacturers  and  others  interested  in  the  art.  He  con- 
sequently set  to  work  to  construct  such  a  book,  with  the 
result  which  is  now  in  the  reader's  hands. 

In  referring  to  the  numerous  sources  of  information 

17477ft 


iv  PREFACE. 

upon  the  subject,  the  Author  was  much  surprised  at  the 
vast  store  of  useful  knowledge  which  was  widely  diffused 
through  a  considerable  number  of  works  and  periodicals 
not  directly  addressed  to  the  trade,  much  of  which  would 
probably  never  come  within  view  of  those  for  whom  it 
was  written.  To  these,  and  the  several  trade  journals — 
The  Leather  Trades'  Circular,  The  Tanners'  and  Curriers' 
Journal,  and  The  Scottish  Leather  Trader — he  gratefully 
acknowledges  his  indebtedness ;  as  also  to  the  several 
works  referred  to  throughout  the  volume. 

80011  after  having  determined  to  undertake  the  present 
work,  the  Author  put  himself  in  communication  with 
several  manufacturers,  requesting  permission  to  have  a 
general  view  of  their  works,  and  to  those  who  kindly 
acceded  to  his  request  he  now  returns  his  warmest  thanks, 
but  more  especially  to  Messrs.  Bevingtons  &  Sons,  the 
eminent  tanners  of  Bermondsey,  and  to  Messrs.  Carlaw 
Brothers,  for  the  generous  spirit  in  which  they  ex- 
plained to  him  the  various  processes  of  manufacture 
conducted  at  their  establishments.  He  has  also  to  thank 
Mr.  Sparke  Evans,  of  the  Avonside  Tannery,  Bristol,  for 
many  useful  suggestions. 

In  conclusion,  the  Author  indulges  a  hope  that  his  effort 
to  supply  an  evident  want  in  English  technical  litera- 
ture, may  meet  with  the  approval  of  his  readers,  and  that 
the  book  will  prove  useful  for  reference  to  everyone  con- 
nected with  the  art. 


PUBLISHERS'  NOTE  TO  THE 
FIFTH   EDITION. 


SINCE  the  issue  (in  181)7)  of  the  Fourth  edition  of  this 
work,  as  revised  by  the  late  Mr.  Alexander  Watt,  rapid 
strides  have  been  made  in  the  Leather  industry.  In  fact, 
so  great  and  constant,  it  appears,  are  the  advances  now 
being  made,  that  it  is  all  but  impossible  to  keep  abreast 
of  them  in  a  technical  Handbook.  The  Publishers  felt 
assured,  however,  that  much  of  the  data  here  collated 
and  prepared  by  Mr.  Watt  was  far  too  valuable  to  be 
cast  aside,  and  having,  after  that  gentleman's  death, 
received  inquiries  from  all  parts  of  the  world  as  to  when 
a  revised  edition  would  be  available,  they  felt  themselves 
fortunate  to  be  able  to  engage  the  services  of  a  well- 
known  expert  who  was  prepared  (within  the  limits 
arranged)  to  thoroughly  revise  the  work,  and  make 
such  additions  as  should  bring  it  up  to  date.  This  was 
by  no  means  an  easy  task,  but  it  is  believed  that  the 
lleviser  (while  retaining  such  parts  of  Mr.  Watt's  work 
us  were  of  permanent  value)  has  succeeded  in  giving, 
also  in  a  condensed  and  easily  digestible  form,  a  sum- 
mary of  most  of  the  modern  methods  now  pursued 
by  Tanners  and  Leather  Manufacturers.  Several  of  the 


VI       PUBLISHERS'  NOTE    TO    THE  FIFTH  EDITION. 

original  chapters,  dealing  with  older-fashioned  leathers 
which  have  practically  passed  out  of  use,  have  been 
omitted,  their  place  being  taken  by  descriptions  of 
tanning  and  dressing  the  more  modern  leathers,  such 
as  chrome,  calf,  and  goat  skins.  In  some  cases,  the 
space  available  would  not  allow  him  to  do  more  than 
give  the  bare  technical  outlines  of  the  processes  in- 
volved ;  and  in  others  the  Keviser  has  had  to  assume  a 
certain  amount  of  knowledge  on  the  part  of  the  reader. 

A  brief  description  has  been  added  of  the  "  Standard  " 
method  of  tannin  estimation,  but  the  scientific  reader 
who  requires  fuller  information  on  this  important  sub- 
ject is  referred  to  Prof.  H.  E.  Procter's  "  Leather  Indus- 
tries Laboratory  Book,"  where  he  will  find  full  justice 
done  to  the  Chemistry  of  Leather  Manufacture.  The 
illustrations  of  machinery  (it  will  be  found)  have  been 
brought  up  to  date,  but  it  will  not  be  forgotten  that 
so  rapid  is  the  progress  made  by  the  Tanner's  Engineer 
that  new  ideas  for  appliances  are  of  almost  daily  occur- 
rence. The  introduction  of  the  Chrome  process  of  leather 
manufacture  was  a  golden  opportunity  for  mechanical 
enterprise,  of  which  British,  American,  and  Continental 
engineers  have  not  been  slow  to  avail  themselves,  and 
they  are  reaping  a  rich  harvest  in  catering  for  the  wants 
of  the  Tanner. 

It  is  right  to  mention  that  the  technical  methods 
described  in  the  work  are  such  as  have  stood  the  test 
of  practical  experience,  and  although  some  of  them  may 
have  to  be  modified  to  suit  individual  special  or  local 
requirements,  yet  it. is  certain  that  students  of  the  sub- 
ject will  obtain  much  that  is  of  real  value  from  an 
intelligent  perusal  of  what  is  here  written.  The  recipes 


PUBLISHERS'  NOTE    TO   THE  FIFTH  EDITION,      vii 

given  are  not  only  actual  working  formula;,  but  many 
of  them  have  been  hitherto  regarded  as  trade  secrets. 

In  conclusion,  the  Publishers  may  be  allowed  to 
( I  note  the  words  of  the  Reviser,  who  has  reminded  them 
that  "  in  the  Manufacture  of  Leather  competition  is 
becoming  keener  year  by  year,  and  the  cost  of  manual 
labour  is  making  it  almost  prohibitive  for  many  pur- 
poses. *  The  old  order  changeth,  giving  place  to  the  new/ 
but  it  is  not  without  a  pang  of  regret  that  even  the  most 
enterprising  man  sees  the  old  forms  of  ancient  skilled 
trades  swept  aside  by  the  march  of  progress.  However, 
this  seems  to  be  one  of  the  inevitable  trading  conditions 
of  the  twentieth  century.  The  day  is  over  when  profit 
could  be  made  easily  and  quickly  in  the  leather  trade, 
and  it  is  only  by  close  study  of  economy  in  the  manu- 
facture, and  careful  organisation  for  the  disposal  of  the 
product,  that  progress  can  be  made.  In  pursuing  the 
former  of  these  two  courses,  close  study,  both  of  the 
science  and  of  the  practice  of  the  Leather  industry,  is 
essential ;  and  if  what  he  has  written  and  compiled  in 
preparing  the  present  edition  is  a  help  in  that  direction, 
the  Reviser  will  feel  that  in  his  attempt  to  bring  the  work 
of  the  late  3Ir.  Watt  into  line  with  modern  methods 
he  will  have  accomplished  a  most  useful  service  for  the 
followers  of  a  most  interesting  calling." 


CONTENTS. 


I'AGR 

INTIIODUCTIOX     .  .....      1 


CHAPTER  I. 
CHEMICAL  THEORY  OF  THE  TAXXING  PROCESS. 

Properties  of  Gelatine — Action  of  Tannic  Acid  on  Gelatine,  &c. — 

Scguin's  Theory  of  the  Art  of  Tunning 11 

CHAPTER  II. 

THE  SKIX. 

The  Skin — Structure  of  the  Skin — Mr.  Ashe's  Description  of  the  Skin 

— Composition  of  the  Skin 23 

CHAPTER  in. 
HIDES  AND  SKINS. 

Classification  of  the  Skins  of  Animals — Condition  of  Hides  and  Skins 
— Hides — Native  Hides — Dried  Hides — Salted  Hides — Dried 
Salted  Hides — Selection  of  Hides — Warbles — Abusive  Treatment 
of  Raw  Hides — Kips — Buffalo  Hides — Horse  Hides — Ass  and 
Mule  Hides — Hippopotamus  Hides — Calves'  Skins — Sheep  Skins 
— Lamb  Skins — Goat  Skins — Kid  Skins — Hog  and  Pig  Skins — 
Seal  Skins — Deer  Skins — Porpoise  Skins — Serpent  and  Croco- 
dile Skins  .  ,  28 


X  CONTENTS. 

CHAPTER   IV. 

TANNIN  OR   T ANN  1C  ACID. 

PAGB 

Tannin  or  Tannic  Acid — Preparation  of  Tannic  Acid — Pelouze's  Pro- 
cess— Berzelius'  Process — Bouillon-Legraiiffe's  Process— Merat- 
Guillot's  Process — Dize''s  Process — Deyeux's  Process — Proust's 
Process — Serturner's  Process — Schering's  Process — Badvil  and 
Lienders'  Process — MM.  Coez's  Process — Kohlrausch's  Process 
— Properties  of  Tannic  Acid — Parnell's  Views — Pure  Tannic 
Acid — Keactions  of  Tannic  Acid — Table  of  the  Percentage  of 
Tannin  in  Vegetable  Substances  —  Morfit's  Observations — 
Artificial  Tannin  .  43 


CHAPTER   V. 

GALLIC  ACID. 

Gallic  Acid — Preparation  of  Gallic  Acid  from  Galls — Scheele's 
Method — Liebig's  Method — Graham's  Method — Pharmaceutical 
Methods— Properties  of  Gallic  Acid — Pyrogallio  Acid — Ellagic 
Acid  ...  57 


CHAPTER  VI. 

GALLIC  FERMENTATION. 
Checking  or  Preventing  Gallic  Fermentation          .         .         .         .     63 

CHAPTER   VII. 

TANNING  MATERIALS. 

Sources  of  Tannin — Barks— Oak  Bark— Barking  of  Trees — Nut 
Galls — Tanning  Extracts — Catechu — Kino — Gambier  or  Terra 
Japonica — Hemlock  Extract — Chestnut  Extract — Oak  wood  Ex- 
tract— Larch  Extract — Quebracho  Extract — Sumac — Khatany 
Root — Mangrove  Extract — Myrobalans — Valonia — Divi  divi — 
Mimosa  Bark — List  of  Tanning  Materials — Miscellaneous  Tan- 
ning Materials .  .68 


CONTEXTS.  XI 

CHAPTER    VIII. 

ESTIMATION  OF  TAN  NIX. 

PACK 

Examination  of  Bark — Determination  by  Specific  Gravity — The 
Barkometer — Chemical  Methods  of  Estimating  Taunin — Davy's 
Method— Bell  Stephens'  Method— Hammer's  Method— Lo'wen- 
thal's  Method— Mr.  Hewitt  on  Luwenthal's  Method— Mr.  Procter 
on  Lo'wenthal's  Method — Ramspacker's  Method — The  Tanno- 
meter — Casali's  Process — Standard  Method — International  Asso- 
ciation of  Leather  Trades'  Chemists  .  .  .  .  .88 

CHAPTER  IX. 

PRELIMINARY  OPERATIONS. 

Treatment  of  Green  or  Fresh  Hides— Method  of  Salting  Hides- 
Cleansing  the  Raw  Hides— Dried  Hides— Softening  Dried  Hides 
—Brain's  Process— Dry  Salted  Hides— Wet  Salted  Hides— 
Schultz's  Views  on  the  Treatment  of  Hides  ....  108 

CHAPTER  X. 

DEPILATJON  OR   UNIIAIRING  SKINS  AND  U1DES. 

Dcpilation  by  Lime — Properties  of  Lime — Storing  the  Lime — Liming 
—Single  Pit  Method — Working  in  Rounds — Continental  Method 
of  Liming — Supposed  Disadvantages  of  the  Lime  Process — Dr. 
Davy  on  the  Action  of  Lime  on  Animal  Matter— Working  on  the 
Beam— Rounding  the  Pelts — Depilution  by  Sweating— Cold 
Sweating— Depilation  by  Acids— Depilation  by  Saccharine 
Matter — Depilation  by  Caustic  Soda— Depilation  by  Bisulphide 
of  Calcium — Depilation  by  Charcoal — Depilation  by  Sulphide 
of  Sodium — Palmer's  Process — Beck's  Process — The  Pullman- 
Payne  Process  .  .  .  .115 

CHAPTER   XL 
RAISING   OR  SWELLING. 

Raising— Bating — The  Bate,  or  Grainer— The  Pure— Scudding — 
Sulphuric  Acid  Bate — Turnbull's  Process — Warrington's  Process 
— Bating  with  Barley-meal— Lactic  Acid  for  Bating— Formic 
Acid  for  Bating  .  »  .  • 138 


xii  CONTENTS. 

CHAPTER  XII 

TANNING  BUTTS  FOR   SOLE  LEATHER. 

PAGE 

Bark  Tanning — Old  Methods  of  Tanning— Modern  System  of  Tanning 
—  Preparation  of  ilie  Ooze — The  Leaches — The  Handlers — The 
Layers — Mixed  Tannages — Tanning  by  Suspension — The  Sus- 
penders— Scouring — Drying  the  Tanned  Butts — Old  American 
Method — The  Drying  Loft — American  Turret  Drier — Working 
of  the  Turret  Drier — Influence  of  Light  upon  Leather — Striking 
—Rolling  the  Leather — To  determine  when  Leather  is  Tanned 
throughout 143 

CHAPTER   XIII. 

TANNING  PROCESSES. 

The  First  English  Patents  for  Tanning — Newton's  Tanning  Process 
— Aldricli's  Process — Orgereau's  Process — Jentriugs's  Process — 
Ballatschano  and  Treuk's  Process — Lomas's  Process — Michel, 
Kollen,  and  Hertzog's  Process — Keasley's  Process  .  .  .109 

CHAPTER   XIV. 

TANNING  PROCESSES— (continued). 

Page's  Process — Casimir  Bez  and  Sons'  Process— Snyder's  Process — 
De  Bock's  Process — Funcke's  Process — Hamer's  Process —Cox's 
Process — Nossitor's  Process — Desmond's  Process  — Burbidge's 
Process— Kleman's  P«oc -ss  .......  191 

CHAPTER   XV. 

TANNING  BY  PRESSURE. 

Spilsbury's    Process — Drake's    Process — Knovvly's   and    Duesbury's 

Process — Fryer,  Watt,  and  Holmes' 0  Process—  Mouren's  Process  206 

CHAPTER   XVI. 

QUICK  TANNING. 

Quick  Tanning — Dr.  Ure's  Views — Dussauce's  Observations — Dietz'e 
Process— Needham's  Process—  Nues&ly's  Process— Bel  I'd  Piocess 
— Baron' a  Procets — Another  Quick  Process — Guiot's  Process — 
Danish  Quick  Process  .  : '  .  .  .  .211 


CONTEXTS.  XIII 

CHAPTER   XVII. 

HARNESS  LEATHER    TANNING. 

I'AOK 

Harness  and  Upper  Leather — Crop  Leather  .... 

CHAPTER   XVIIL 

AMERICA*   TANNING. 

Cold  Sweating  of  IIioV»— Sweat  Pits— Treatment  of  Hides  in  the 
Sweat  Pita — Treatment  of  Hides  after  Sweating — Liming — Uu- 
hairing  by  Prof.  Lupkin's  Process  —  Benin  Work — Trimming  or 
Hounding— Grinding  the  Bark — Learning — The  "  Press  "  Leadi 
— Raising  with  Vitriol — llandliug — The  Rocker  Handler — The 
Layers.  .  22S 

CHAPTER  XIX. 

HEMLOCK    TANNING. 

Pratl'rt  Svstem  of  Tanning — Hemlock  Tanning  of  Xew  Lebanon — 

Hibberd's  Process  .  .   215 

CHAPTER   XX. 

TANNING  BY  ELECTRICITY. 

Ward's  Pmceos— Gaulard's    Process— Gaulard's    Second    Process— 

Meriien'e  Process — Crosse's  Process          .....  254- 

CHAPTER  XXI. 

CHEMICAL  TANNING. 

Knapp's   Processes—  Heinzerling's  Chrome   Process—  Ileinzerling's 

Second  Chrome  Process — Vanderstmaicu's  Process  .         .         .  2CO 

CHAPTER    XXII. 

MISCELLANEOUS  PROCESSES. 

Indian  Method  of  Preparing  Elk  skins — Old  Irish  Process  of  Tanning 
—  Tanning  Nets,  Sails,  and  Cordage — Glycerine  in  Tanning- 
Bleaching  Leather  . 268 


xiv  CONTENTS. 

CHAPTER  XXIII. 

PACK 

ON  THE   COST  OF  AMERICAN  TANNING    .        .     272 

CHAPTER  XXIV. 

MANUFACTURE   OF  LIGHT  LEATHERS. 

Russia  Leather — Count  Kartstoff's  Description  of  Ru-sia  Leather 
Manufacture — Smoking  Skins — Another  Method  of  Preparing 
Russia  Leather — Black  Russia  Leather — Yufts  Russia  Leather 
- — Morocco  Leather — Sumac  Tanning  —  Imitation  Morocco 
Leather — Skiver — Cordovan  Leather — Roan — Hungary  Leather 
— Wallachia  Leather — Barley  Dressing — Morfit's  Remarks  on 
\Vhite  Dressing — lied  Dressing — Brau  Dressing — Enamelled 
Leather 27G 

CHAPTER   XXV. 

D  YE  ING   LEA  TH Eli. 

Dyeing  Morocco  Leather — Dyeing  \\ith  Aniline  Colours — Dyeing 
Kid  Leather  for  Boots — Bath  Dyeing — Dyeing  on  a  Flat  Surface 
— Aniline  Colours  in  Glove  Dyeing — Dyeing  with  Pure  Aniline 
Colours  ..........  299 

CHAPTER   XXVI. 

MANUFACTURE   OF  WHITE  LEATHER. 

Tawing  as  Distinguished  from  Tanning — Tawing  Operations — Kid 
Leather  :  Treatment  of  Kid  Skins — French  Kid  Leather — 
Imitation  Kid — Continental  Method  of  Preparing  Glove  Leather 
—Calf  Kid  for  Uppers— White  Sheep  Leather— Splitting  Sheep 
Skins 306 

CHAPTER   XXVII. 

CHROME  LEATHER  MANUFACTURE. 

Preliminary  Operations —Liming  and  Unhairing — Fleshing — Puring 
or  Deliming— Scudding  —  Chroming  Operations— Striking-out 
and  Shaving — Dyeing  Chrome  Leather — Fat  Liquoring— Dye- 
ing Black— Putting  or  Striking-out— Oiling  and  Drying- 
Staking  or  Softening  -Seasoning— Glazing  .  .  .  .323 


CONTENTS.  XV 

CHAPTER   XXVIII. 

BOX-CA LF  J/.-l  NUFACTURE. 

PAGE 

Striking-out  and  Shaving— Fat  Liquoring— Dyeing  Block— Finish- 
ing Operations  ..... 

CHAPTER  XXIX. 

CHAMOIS,  Oil  OIL-LEATHER  MANUFACTURE. 
Preparation  and  Frizing— Drenching— Stocking  or  Milling  in  Oil — 
Pressing  and  Washing— Finishing — Chamois  Glove  Leather — 
Bleaching— Tucking—  Colouring— Buff  Leather — Liming — Pre- 
paring and  Milling — Spudding  and  Wash-house— Buck  Skin 
Dressing— Milling  or  Stocking — Scudding  and  Wash-house  .  357 

CHAPTER   XXX. 

CURRYING. 

The  Scouring-hoiK-e— The  Shop— The  Curriers'  Knife— Currying 
Kip  Leathers — Waxed  Kip  Butts — Sorting  and  Rounding — 
Soaking  and  Softening — lie-tanning — Drum-stuffing — Setting — 
Finishing — Stoning  and  Starching — Graining — Waxing — Top- 
sizing — Currying  Satin  or  Glove  Shoe  Leather— Soaking  and 
Splitting— Buffing— Blacking  and  Setting — Finishing  Satin  or 
Glove  Leather — Levant  Leather— Soaking  and  Splitting- 
Setting,  Buffing,  and  Embossing— Black— Seasoning  and  Glaz- 
ing— Oiling — Currying  Various  Leathers — Wax  Calf  Skins — 
Calf  Skins  for  Memel— High  Shoes,  Black  Grain— Split  Cow- 
hides for  Brown  Bags— Blocking  Boot-fronts  .  .  .  .368 

CHAPTER  XXXI. 

MACHINERY  EMPLOYED  IN  LEATHER  MANUFACTURE. 

"Stocking  "  or  Softening  Machines— Dcpilution  and  Fleshing  Plant 
— Machines  for  Crushing  and  Grinding  Tanning  Materials — Sole 
Leather  Finishing  Machinery — Leather  Dressing  Machinery — 
Scouring  and  Setting  Machinery— Embossing  and  Softening 
Machinery— Tanning  and  Stuffing  Drums — "Boarding"  and 
Softening  Machines  —  Machinery  used  in  Chrome  Leather 
Manufacture — Machinery  used  in  the  Beam  House— Finishing 
Machinery  for  Chrome  Work  .  .  ...  399 


XVI  CONTENTS. 

CHAPTER   XXXII. 

EMBOSSING  LEATHER. 

PAGB 

Copying  Crocodile,  Alligator,  &c.,  Skins         .....  431 

CHAPTER   XXXIII. 

FELLMONGERING. 
Classification  of  Sheep  Skins— Treatment  of  tlie  Skins    .         .         .  434 

CHAPTER   XXXIV. 

PARCHMENT,  VELLUM,  AND  SHAGREEN. 

Preparation  of  Parchment  and  Vellum — Skins  for  Drumheads — Sha- 
green— Fish  Skin,  or  Fish  Shagreen 437 

CHAPTER   XXXV. 

GUT-DRESSING. 

Preparation  of  Cattle  Intestines :  Continental  Method — Goldbeaters' 
Skin— Lathe  Cords — Cords  from  Sheep  Intestines— Cords  for 
Tennis  Bats,  &c. — Whipcords — Gut  Strings  for  Musical  Instru- 
ments ...........  441 

CHAPTER   XXXVI. 

GLUE-BOILING. 

Treatment  of  Glue-pieces,  &c. — French  Glue — Parchment  Glue — 

Size— Glue  Waste          . 449 

CHAPTER   XXXVII. 

UTILISATION  OF  TANNERS'1   WASTE. 

Spent  Tan— Guest  and  Court's  Process— Hide  and  Skin  Cuttings- 
Hair  Waste — Lime  Waste -Glucose  in  Leather  .  .  .  455 

INDEX        .  '•         •  462 


TY   ; 


THE  ART 

OP 

T 17  A  TUTR     ¥  A  ATTTP  A  f!TTTl>17 

ERRATA   IN  TEXT. 

Pago  vi.,  line  5,  for  '  chrome,  calf '  read  '  chrome  calf.' 
„     xi.,    „    G,  for  '  Mr.  Procter  '  read  '  Prof.  Procter.' 
,,     xi.,    „     8,  for  'Standard    Methods— International   Association' 
read  '  Standard   Method  of   the   International  Asso- 
ciation.' 

,,    xi.,    ,,  29  (Chapter  Heading),  for  '  Raising  or  Swelling  '  read  'De- 
liming  or  Bating.' 

,,    xv.,    „  21,  for  '  Black  '  read  '  Blacking.' 
„    xv.,    ,,  29,  for  '  Leather  Dressing  Machinery'  read  '  Shaving  and 

Splitting  Machinery.' 

,,    88,     ,,    6,  for  « Mr.  Procter  '  read  '  Prof.  Procter.' 
,,    88,     ,,    8,  for    'Standard     Method. — International    Association' 
read  'Standard    Method  of  the  International  Asso- 
ciation.' 

138-142  (Chapter  Heading),  for  '  Raising  or  Swelling  '  read  '  De- 
liming  or  Bating.' 

Page  399,  line  6,  for  '  Leather  Dressing  Machinery '  read  '  Shaving  and 
Splitting  Machinery.' 


WATT'S  4  LEATHER  MANUFACTURE.' 


with  greater  economy  and  certainty,  while  Chemical 
Science  has  furnished  him  with  an  abundance  of  tanning 
materials  of  which,  without  such  aid,  he  would  doubt- 
less have  remained  in  ignorance.  Moreover,  various 

B 


XVI  CONTENTS. 

CHAPTER  XXXII. 

EMBOSSING  LEATHER. 

PAGK 

Copying  Crocodile,  Alligator,  &c.,  Skins 4oi 


opent  Tan — v^uest  ana  i^ouri  s  process — xiiae  ana 

Hair  "Waste — Lime  Waste— Glucose  in  Leather        .         .         .  455 

INDEX        .         . 462 


THE  ART 


OF 


LEATHER  MAMFAOTURE. 


INTRODUCTION. 

IN  future  ages  the  past  century  will  ever  be  famous, 
not  only  for  its  important  discoveries  and  useful  inven- 
tions, but  it  will  also  be  marked  as  an  era  in  which, 
however  tardily  at  first,  the  teachings  of  Science  were 
accepted,  and  many  useful  arts  rescued  from  empiricism 
and  ignorance.  Even  within  the  memory  of  many  now 
living,  the  innovations  of  Science  were  formerly  looked 
upon  with  suspicion,  as  being  not  only  unnecessary  but 
possibly  fraught  with  mischief.  What  could  chemists 
know  about  soap-making,  or  of  the  art  of  tanning  hides  ? 
If  good  soap  and  good  leather  could  be  produced  for  so 
many  generations  without  the  aid  of  Science,  why  not 
continue  in  the  same  track  as  of  old  ?  Reflections  such 
as  these  inspired  the  workers  in  these  arts  for  a  long  time 
after  they  were  proved  to  be  based  upon  definite  chemical 
laws  ;  and  it  is  well  known  that  a  deaf  ear  was  turned  to 
those  who  ventured  to  assert,  and  even  to  prove,  that 
chemistry  was  indissolubly  allied  to  those  arts  which  had, 
from  time  immemorial,  been  conducted  chiefly  by  the 
judgment  of  uneducated  workmen. 

Although  it  must  be  confessed  that  the  discovery  of  the 
chemical  principles  involved  in  the  art  of  tanning  has  not, 
in  its  application,  improved  the  quality  of  leather,  still  this 
important  knowledge  has  enabled  the  tanner  to  work 
with  greater  economy  and  certainty,  while  Chemical 
Science  has  furnished  him  with  an  abundance  of  tanning 
materials  of  which,  without  such  aid,  he  would  doubt- 
less have  remained  in  ignorance.  Moreover,  various 

B 


2  LEATHER  MANUFACTURE. 

methods  of  quickening  the  process  of  tanning  have  been 
introduced  which,  in  their  turn,  have  facilitated  the  pro- 
duction of  leather  to  meet  the  ever-increasing  demand  for 
this  valuable  article  of  universal  requirement. 

Respecting  the  early  history  of  tanning,  some  very 
interesting  facts  are  given  in  the  Gerber  Courier  of 
Vienna,  from  which  we  extract  the  following : — "  The 
oldest  method  of  tanning  is  red  or  bark  tanning,  or  that 
in  which,  in  addition  to  the  wooden  and  iron  scraping  and 
rubbing  instrument  used  in  the  preparation  or  improve- 
ment of  the  hide  or  skin,  limewater  and  astringent 
extracts  from  oak  and  other  kinds  of  bark,  or  from  other 
vegetable  substances,  are  employed.  It  is  called  red 
tanning  because  the  tanning  substances  always  contain 
more  or  less  colouring  matter,  which  dye  the  leather 
through  and  through  of  a  more  or  less  reddish  colour. 
The  ancient  Orientals  understood  the  art  of  preparing  not 
only  common  leather,  but  even  good  and  often  finely 
coloured  varieties,  similar  to  our  Morocco  and  Cordovan. 
Persian  and  Babylonian  leather  has  been  celebrated  time 
out  of  mind.  Many  centuries  back  such  leather  was 
brought  from  Asia  into  Europe — first  into  Turkey,  Prussia, 
and  Hungary,  and  thence,  later,  into  Germany,  Holland, 
England,  France,  Spain,  &c.,  and  these  countries  subse- 
quently learned  to  manufacture  leather  themselves.  In 
the  first  centuries  of  Christianity,  the  Turks,  Russians,  and 
Hungarians  were  the  most  celebrated  tanners;  subse- 
quently England,  the  Netherlands,  and  Spain  endeavoured 
to  equal  them. 

"Among  five  sorts  of  leather  of  foreign  origin,  Cor- 
dovan, Morocco,  Shagrin,  and  Russian  leather  have  at  all 
times  been  specially  famous.  Cordovan,  a  soft,  small- 
grained,  coloured  leather,  had  already  been  prepared  by 
the  ancient  Orientals.  Its  name  is  derived  from  the 
Spanish  city  of  Cordova,  whence  it  was  possibly  first 
introduced  into  Europe,  and  where,  for  a  long  time  after- 
wards, it  was  chiefly  manufactured.  It  enjoyed  a  great 
reputation  in  the  eleventh  century,  when  the  most  dis- 
tinguished persons  wore  shoes  of  Cordovan  leather.  The 


INTRODUCTION.  3 

French  name  for  shoemaker,  *  cordonnier/  appears  also 
to  have  been  derived  from  this  leather.  From  the  gradual 
improvement  of  Cordovan,  sprang  Morocco,  called  also 
Turkish  and  Spanish  leather.  This  beautifully  coloured 
and  brilliant  leather  has  always  been  most  excellently 
manufactured  in  Morocco,  in  European  and  Asiatic  Turkey, 
in  KrimTartary,  in  the  Island  of  Cyprus,  &c.,  and  very 
well  also  in  Russia,  Poland,  Hungary,  and  Spain,  but 
especially  in  England,  France,  Holland,  and  Germany. 

"  Shagrin  (in  Turkish  Sagri,  and  Persian  Sagre)  is 
chiefly  celebrated  for  its  hardness  and  strength,  and  for 
the  peculiarity  of  its  grain  side,  which  appears  as  if 
covered  with  globular  granules.  It  is  also  of  Eastern 
origin.  The  best  Shagrin  is  now  made  in  Persia,  Con- 
stantinople, Algiers,  and  Tripoli.  The  production  of  the 
small  globular  granules  on  the  grain  side  was  for  a  long 
time  kept  secret.  We  were  first  informed  by  the  cele- 
brated traveller,  Pallas,  that  they  were  produced  by 
stamping  the  hard  seeds  of  the  wild  orach  ( Chenopodium 
allium]  into  the  hide  spread  on  the  ground.  The 
seeds  were  afterwards  knocked  out,  and  the  hide  scraped 
on  the  indented  side  and  soaked  in  water  for  two  days. 
The  Hungarians  were,  in  ancient  times,  especially  cele- 
brated for  their  white  tanned  leather,  which  was  imitated 
in  France  as  long  ago  as  three  hundred  years. 

"We  beg  our  readers  to  go  back  some  centuries  in 
history,  and  they  will  be  convinced  that  the  products  of 
our  trade  were  known  in  the  time  of  Moses ;  for  at  that 
period  leather  carpets  were  already  used  in  tents.  These 
we  may  still  meet  with  among  the  Arabs.  Coloured 
leather  seems  also  to  have  been  common,  for  Ezekiel 
speaks  of  fine  red  leather,  which  was  probably  our 
splendid  red  Morocco.  Leather  was  also  used  in  the 
remotest  ages  by  the  Israelites  as  a  material  to  write 
upon,  for  they  used  strips  made  of  leather  for  this  pur- 
pose. According  to  the  testimony  of  Herodotus,  the 
ancient  Ismians  wrote  their  annals  upon  sheepskin,  and 
the  ancient  Persians  likewise,  according  to  Diodorus  of 
Sicily.  According  to  Herodotus,  the  ancient  Lib}rana 


4  LEATHER  MANUFACTURE. 

wore  leather  clothing ;  the  Ichthyophagists  on  the  banks 
of  the  Araxes  dressed  themselves  in  sealskins;  and  in 
the  time  of  Alexander  the  wild  inhabitants  of  Geodrosia 
used  the  hides  of  animals  for  clothing,  and  covered  their 
dwellings  with  leather.  Homer  praises  the  splendid  half- 
boots  of  Agamemnon,  and  Hesiod  recommends  leather 
shoes  lined  with  fur.  For  many  years  leather  was  used 
by  the  Greeks -in  the  construction  of  ships,  especially  by 
the  Phoenicians,  who  originally  inhabited  an  arid,  sandy 
corner  of  the  earth  between  the  Red  Sea  and  the  Mediter- 
ranean, where  the  soil  was  not  favourable  to  the  growth  of 
timber,  and  they  were  obliged  to  supply  its  place  by 
covering  their  boats,  constructed  of  willows  woven  to- 
gether, with  leather  or  hides,  which,  even  thus  early, 
were  subjected  to  a  certain  amount  of  dressing.  The 
ancient  Germans  also,  who  lived  on  the  sea-coast,  and 
the  original  Britons,  equally  possessed  this  custom. 

"It  is  asserted  that  the  art  of  dressing  leather  in 
general,  upon  the  so-called  Hungarian  method,  was  first 
brought  from  Senegal,  in  Africa,  and  made  known  to  us 
in  the  middle  of  the  sixteenth  century  by  Buscher,  the 
son  of  a  tanner  in  Paris.  At  that  time  leather  was  com- 
mon in  Hungary,  and  dressed  leather  was  very  highly 
esteemed.  In  the  year  1584  two  German  tanners,  named 
Lasmagne  and  Aurand,  came  to  Neufchatel,  in  Lorraine, 
where  they  worked  at  their  trade  ;  from  thence  they  went 
to  St.  Deziers,  in  Champagne,  and  finally  to  Paris,  where 
they  prepared  very  good  leather.  The  theory  that  the 
preparation  or  tanning  of  the  hides  was  discovered  cen- 
turies ago,  and  that  the  leather  produced  was  employed 
for  the  same  purposes  as  at  present,  is  further  confirmed 
by  the  following  old  proverb,  which  is  proof  that  leather 
shoes  were  already  worn  at  that  time  :  *  "We  must  not 
steal  leather  to  give  away  shoes  in  God's  name.'  This 
refers  to  the  legend  of  St.  Crispin,  who  stole  leather  to 
make  shoes  out  of  it  for  the  poor.  In  the  old  form  of 
speech,  *  to  draw  from  the  leather '  signified  to  draw  the 
sword.  In  low  Saxon  the  same  expression  signifies  to 
undress." 


INTRODUCTION.  5 

Although  the  preceding  observations  indicate  that  the 
writer  believed  that  the  art  of  converting  skins  and  hides 
into  leather  was  not  only  exceedingly  ancient,  but  also 
widely  diffused,  it  is  equally  probable — except  among  the 
early  Egyptians,*  who  must  have  known  a  comparatively 
high  state  of  civilisation — that  the  so-called  leather  was 
in  reality  the  skin  or  hide  of  the  slaughtered  animal 
merely  dried  in  the  sun  or  smoke-cured,  and  not  what  we 
understand  by  the  term  leather.  Indeed  it  is  well  known 
that  untanned  skins  have  from  all  time  been  used  by  un- 
civilised tribes  (as  is  also  the  case  at  the  present  time)  for 
clothing  and  many  other  purposes.  In  some  parts  of 
France,  even  at  the  present  day,  bottles  are  made  from 
skins  of  animals  sewn  up,  and  are  used  for  the  conveyance 
of  wine  and  oil.  The  skins  of  animals  were  also  used  for 
making  vessels  to  contain  liquids — even  wine ;  but  it  is 
more  than  probable  that  the  skins  were  merely  dried  in 
the  sun  and  then  externally  greased  to  render  them  pliant 
and  preserve  them  from  the  effects  of  moisture,  or  were 
cured  by  smoking,  and  not  tanned  in  the  ordinary  sense. 
In  support  of  this  view,  David,  in  Psalm  cxix.  83,  says, 
"  I  am  become  like  a  bottle  in  the  smoke,"  which  would 
indicate  that  the  (skin)  bottles  in  his  time  were  cured  by 
smoking.  The  preservative  effects  of  the  volatile  matters 
given  off  by  burnt  wood  were  doubtless  known  at  the 
earliest  periods,  and  it  is  therefore  reasonable  to  infer  that 
the  Psalmist  alluded  to  this  mode  of  preserving  bottles 
made  from  the  skins  of  smaller  animals.  Again,  in  the 
preceding  verse,  David  says,  "  Mine  eyes  fail  for  thy 
word  ;  "  may  not  this,  taken  in  conjunction  with  his  sub- 
sequent complaint,  indicate  that  his  vision,  being  impaired, 
caused  him  to  behold  objects  as  through  a  mist — "  like  a 
bottle  in  the  smoke."  Job,  in  chap.  xxx.  30,  says,  "  My 
skin  is  black  upon  me,  and  my  bones  are  burnt  with  heat," 

*  In  the  Egyptian  collection  of  the  British  Museum  may  be  seen  a 
leather  workman's  apron,  with  a  small  purse-shaped  pocket  at  the  right 
side  ;  leather  shoes  with  round  toes,  ankle  and  fore  straps,  most  of  them 
for  children ;  also  other  shoes  of  coarser  and  stouter  make,  and  sandals  of 
various  forms  and  sizes  ;  shoes  with  high  peaked  toes  ;  rolls  of  prepared 
leather  of  a  maroon  colour,  a  yoke  with  one  leather  strap  remaining,  &c* 


6  LEATHER  MANUFACTURE. 

probably  also  comparing  his  lamentable  condition  to  that 
of  a  bottle  being  cured  by  the  smoke  from  burnt  wood. 
Our  Saviour  refers  to  the  necessity  of  putting  new  wine 
into  new  bottles,  "else  the  new  wine  doth  burst  the  bottles." 
Assuming  that  such  bottles  were  made  from  the  skins  of 
animals,  it  is  obvious  that  in  course  of  time,  through  long 
use,  they  would  become  perished,  as  it  is  termed,  and  in 
such  a  brittle  condition  as  to  render  them  incapable  of 
withstanding  the  pressure  of  new  wine. 

In  ancient  writings  the  words  skin  and  leather  are  evi- 
dently synonymous,  but  probably  refer  to  the  dried  or 
cured  skin.  Kennett,  in  his  Antiquities  of  Rome,  speak- 
ing of  the  shoes,  slippers,  &c.,  worn  by  the  ancient  Romans, 
says,  "The  perones  were  a  kind  of  high  shoes,  rudely 
formed  of  raw  hides,  and  reaching  up  to  the  middle  of  the 

leg Dacier   tells   us   that  the  senators   had   two 

sorts  of  shoes,  one  for  summer  and  the  other  for  winter. 
The  winter  shoes  were  made  of  an  entire  black  skin,  or 
sometimes  a  white  one,  reaching  up  to  cover  the  greater 
part  of  the  leg,  without  any  open  place  except  at  the  top. 
....  It  is  uncertain  whether  the  cakei  mullci  (red 
shoes)  were  so  called  from  the  colour  of  the  mullet,  or 
whether  they  lent  a  name  to  that  fish  from  their  reddish 
dye.  They  were  at  first  the  peculiar  wear  of  the  Alban 

kings,  afterwards   of  the   kings  of  Rome Julius 

Csesar,  who  was  very  singular  in  his  whole  habit,  was 
particularly  remarkable  for  wearing  mullei  on  ordinary 

days The  Roman  soleae  were  a  sort  of  sandals, 

without  any  upper  leather,  so  that  they  covered  only  the 
sole  of  the  foot,  being  fastened  above  with  straps  and 
buckles.  These  were  the  ordinary  fashion  of  the  women, 

and  therefore  counted  scandalous  in  the  other  sex 

The  crepida  had  two  soles,  whereas  the  solea  consisted 
but  of  one.  The  former  word  is  supposed  to  be  derived 
from  crepitus,  creaking,  from  the  peculiar  sound  which 
the  double  soles  produced.  Momus,  when  brought  to 
censure  Venus,  could  find  no  fault  in  her  except  that  her 
slippers  creaked  a  little  too  much  ! "  The  Romans  appear 
to  have  acquired  a  knowledge  of  leather  manufacture  at  a 


INTRODUCTION.  7 

later  period,  and  to  have  pursued  it  with  great  success.  It 
is  said  that  boots  and  shoes  equal  to  those  of  the  present 
age  were  worn  by  Roman  ladies,  and  Pliny  alludes  to  hides 
being  tanned  with  bark,  and  also  states  that  gall  nuts, 
sumach,  and  lotus  bark  were  employed  in  tanning. 

About  1300  A.D.,  embossed  leather  of  great  beauty  was 
produced,  specimens  of  which,  in  the  form  of  tapestry,  are 
still  preserved  in  some  of  our  old  English  mansions. 
Spain,  Italy,  Flanders,  and  England  were  famous  for  the 
production  of  embossed  leather  richly  coloured  and  gilt. 
This  art  having  also  been  practised  by  the  early  Egyptians 
nearly  three  thousand  years  ago,  it  is  probable  that  the 
countries  above  named  may  have  revived  and  improved 
upon  the  Egyptian  art. 

It  was  not  until  the  end  of  the  eighteenth  century,  and 
the  commencement  of  the  nineteenth,  that  the  subject  of 
tanning  received  the  attention  of  scientific  men,  and  the 
great  result  of  their  investigations  was  that  the  principles 
of  the  process  of  tanning  were  fully  developed,  and  the 
chemical  action  of  the  tanning  agents  upon  the  pelt,  or  un- 
haired  skin,  definitely  determined.  The  researches  of 
Lewis,  Deyeux,  Seguin,  Macbride,  Prevost,  and  Sir 
Humphry  Davy  established  the  fact  that  the  process  of 
tanning  was  a  chemical  art,  and  as  such  should  be  con- 
ducted with  a  due  amount  of  scientific  method.  But  many 
years  elapsed— nearly  half  a  century,  indeed— before 
tanners  would  recognise  any  suggested  improvement. 

Up  to  about  seventy  years  ago  the  tanners  were  men  of 
small  means,  diffused  throughout  the  country,  unaided  by 
railway  communication  and  the  advantages  of  machinery, 
while  being  utterly  free  from  any  knowledge  of  chemical 
principles.  As  a  contrast  to  this  condition  of  the  trade, 
we  have  now  an  accumulation  of  extensive  tanneries, 
many  of  which  are  situated  near  the  great  ports  where 
the  raw  materials  are  landed  from  abroad ;  and  the 
capital  invested  in  these  establishments  runs  into 
several  millions.  In  some  of  these  the  principles  of 
the  art  are  not  only  understood  but  more  or  less 
generally  followed,  while  the  advantages  of  labour-saving 


8  LEATHER  MANUFACTURE. 

machinery  have  been  recognised,  and  mechanical  appli- 
ances adopted  which  the  tanners  of  old  would  have  looked 
at  but  to  condemn. 

As  the  principles  of  tanning  became  better  understood, 
many  attempts  were  made  to  hasten  the  tardy  conversion 
of  skins  into  leather,  some  of  which,  emanating  from 
practical  tanners,  being  not  only  ingenious,  but  possessing 
the  merit  of  being  of  a  fairly  practical  nature.  The  first 
of  these  processes  was  due  to  Francis  Spilsbury,  who,  in 
1823,  took  out  a  patent  for  a  process  by  which  the  tanning 
liquor  was  forced  through  the  skins  by  hydrostatic  pres- 
sure. A  modification  of  this  process  was  introduced  by 
William  Drake  in  1831,  which  consisted  in  having  two 
skins  sewn  together,  forming  a  watertight  bag,  in  which 
the  tanning  liquor  was  introduced  by  means  of  a  funnel  ; 
the  bag  being  thus  filled,  was  kept  constantly  in  this  con- 
dition until  the  tanning  was  complete.  In  1826,  Messrs. 
Knowlys  and  Duesbury  procured  a  patent  for  hastening 
the  impregnation  of  the  skins  with  tanning  liquor  by  sus- 
pending them  in  a  close  vessel,  from  which  the  air  could 
be  exhausted  by  means  of  an  air-pump.  By  this  method 
the  skins  were  said  to  be  so  effectually  impregnated  with 
tannin  that  their  conversion  into  leather  was  greatly 
accelerated. 

Many  other  mechanical  contrivances  have  from  time  to 
time  been  introduced,  with  a  view  to  promote  the  rapid  and 
uniform  absorption  of  tannin  by  the  skins,  amongst  which 
may  be  mentioned  Nossiter's  plan  of  separating  the  skins, 
while  in  the  tan  liquor,  by  wooden  frames  or  partitions  ; 
Keasley's  arrangement  for  raising  and  lowering  the  skins 
alternately  during  the  tanning  operation,  as  a  substitute 
for  "handling;"  and,  more  recently,  Bez  and  Sons' 
method  of  tanning  hides  by  means  of  a  continuous  flow  or 
current  of  tanning  liquor.  These  and  other  processes  will 
be  described  in  the  subsequent  pages. 

Since  the  period  when  Davy  examined  the  chief  tannin- 
yielding  plants  known  in  his  time,  a  vast  number  of  vege- 
tables have  contributed  to  the  tanner's  list  of  tanning 
materials,  some  of  which,  employed  either  alone  or  mixed 


INTRODUCTION.  9 

with  other  sources  of  tannin,  have  proved  highly  service- 
able in  the  production  of  leather.  Amongst  these  may  be 
mentioned  hemlock,  valonia,  mimosa,  divi  divi,  myroba- 
lans,  quebracho,  &c.  The  foremost  of  these — hemlock- 
is  the  chief  tanning  agent  of  the  Northern  States  of 
America,  in  which  it  abounds  in  unlimited  prolusion. 
Oakwood  and  chestnut  extract  is  also  largely  imported 
into  this  country  from  Canada  and  the  Continent. 

Many  methods  have  been  devised  for  the  estimation  of 
tannin,  but  the  system  proposed  by  Lowenthal,  and  some- 
what modified  by  our  own  chemists,  is  now  generally  ac- 
cepted as  the  most  reliable.  While  the  simpler  methods 
of  determining  the  percentage  of  tannin,  by  the  amount  of 
gelatine  required  for  its  precipitation,  or  by  the  amount  of 
tannin  which  a  given  weight  of  dried  skin  absorbs,  will 
afford  an  approximate  estimate  of  the  proportion  of  tannin 
in  a  sample  of  bark  or  other  tannin  material,  Lowenthal's 
method  is  capable  of  giving  far  closer  and  more  reliable 
results  than  any  other  at  present  known.* 

Expatiating  on  the  importance  and  extent  of  the  leather 
manufacture  in  this  country,  Dr.  Campbell  says  :  "  If  we 
look  abroad,  on  the  instruments  of  husbandry,  on  the  im- 
plements used  in  most  mechanical  trades,  on  the  structure 
of  a  multitude  of  engines  and  machines  ;  or  if  we  contem- 
plate at  home  the  necessary  parts  of  our  clothing — shoes, 
boots,  and  gloves— or  the  furniture  of  our  houses,  the 
books  on  our  shelves,  the  harness  of  our  horses,  and  even 
the  substance  of  our  carriages,  what  do  we  see  but  in- 
stances of  human  industry  exerted  upon  leather  !  What 
an  aptitude  has  this  single  material,  in  a  variety  of  circum- 
stances, for  the  relief  of  our  necessities  and  supplying 
conveniences  in  every  state  and  stage  of  life !  Without 
it,  or  even  without  it  in  the  plenty  we  have  it,  to  what 
difficulties  should  we  be  exposed  ! 

*  Since  the  above  was  written,  the  "  Standard  Method,"  as  adopted 
by  the  International  Association  of  Leather  Trade  Chemists,  ia  now 
generally  used  by  European  chemists  for  tannin  estimation.  A  con- 
densed description  of  this  is  given  at  the  end  of  chap.  viii.  p.  104. — ED 
Fifth  Edition. 


io  INTRODUCTION. 

While,  in  the  early  part  of  the  past  century,  the 
soapmaker  was  constantly  under  the  surveillance  of  the 
exciseman,  the  tanner  was  equally  favoured  by  the  con- 
stant presence  of  that  official  supervisor ;  at  the  soap- 
works,  the  coppers  were  locked  and  unlocked  night  and 
morning  by  the  exciseman,  while  at  the  tanyard  not  a 
single  hide  could  be  shifted  without  his  supervision,  and 
in  the  case  of  any  breach  of  the  excise  laws  heavy  penalties 
were  inflicted.  In  the  year  1830  the  leather  tax  was 
abolished,  and  as  evidence  of  the  great  impetus  which  this 
caused  to  the  trade,  in  the  year  1828  the  value  of  exports 
of  leather  and  saddlery  were,  collectively,  £183,361,  while 
in  1882  these  exports  amounted  to  £2,348,242. 

Since  that  date,  British  trade  in  leather  and  leather 
goods  has  shown  continued  expansion.  In  1905,  leather 
to  the  value  of  £2,112,823  was  exported,  boots  and 
shoes  £1,882,294,  and  saddlery  and  harness  to  the  value 
of  £518,082.  This,  it  must  be  remembered  too,  has 
been  done  in  the  face  of  ever-increasing  hostile  tariffs, 
for  even  the  Australian  Commonwealth  has  so  raised  the 
import  duties,  that  it  now  only  pays  to  send  the  finest 
classes  of  leather  goods  to  the  Antipodes. 


CHAFTEU  I. 
CHEMICAL  THEORY  OF  THE  TANNIXG  PROCESS. 

Properties   of   Gelatine.— Action   of   Tannic   Acid   on   Gelatine,   &c. — 
Seguin's  Theory  of  the  Art  of  Tanning. 

THE  process  of  tanning  consists  in  the  conversion  of  the 
skins  of  animals  into  leather,  by  chemically  combining 
with  the  substance  of  the  skin  an  astringent  vegetable 
principle  called  tannin,  or  tannic  acid;  and  in  order  to 
thoroughly  understand  why  this  conversion  takes  place 
when  skins  are  immersed  in  a  solution  of  the  tanning 
principle,  we  must  know  something  of  the  chemical  com- 
position of  the  skin  itself.  When  the  cuticle,  or  scarf 
skin,  has  been  removed  from  the  cutis,  or  true  skin,  it  is 
found  that  the  latter  is  almost  entirely  soluble  when  boiled 
in  water,  and  the  solution,  after  evaporation  and  cooling, 
sets  into  a  jelly — this  is  gelatine,  a  substance  which 
readily  combines  with  tannic  acid.  Gelatine  is  also 
obtained  in  the  same  way  from  bones,  cartilages,  ten- 
dons, and  ligaments.  The  purest  form  of  gelatine  is 
isinglass,  prepared  from  the  air-bladders  and  sounds  of  the 
sturgeon. 

Properties  of  Gelatine. — Pure  gelatine  is  colourless, 
without  odour,  insipid  to  the  taste,  and  transparent ;  it  is 
more  or  less  tough,  according  to  the  source  from  which  it 
is  obtained.  It  is  heavier  than  water,  and  when  heated, 
it  first  becomes  soft,  and  then  shrinks.  When  burned,  it 
exhales  an  odour  resembling  that  of  burnt  horn.  In  cold 
water  gelatine  softens  and  swells,  but  only  partially  dis-' 
solves ;  with  gentle  heat,  however,  it  dissolves  freely. 
Good  glue,  immersed  in  cold  water,  absorbs  about  three  or 
four  times  its  own  weight  of  that  liquid  without  dissolving. 


12  LEATHER  MANUFACTURE. 

One  part  of  isinglass  dissolved  in  100  parts  of  water,  gela- 
tinises on  cooling ;  but  in  150  parts  of  water  it  remains 
liquid;  the  gelatinising  of  the  solution,  however,  will 
naturally  depend  upon  the  temperature  of  the  atmosphere 
and  the  quality  of  the  gelatine.  The  skins  and  tissues  of 
the  older  animals  yield  a  firmer  jelly  than  those  from 
younger  ones.  According  to  Brande,  when  a  solution  of 
gelatine  is  repeatedly  warmed  and  cooled,  more  especially 
if  it  be  boiled,  it  gradually  loses  its  tendency  to  gelatinise, 
and  becomes  more  and  more  soluble.  In  close  vessels 
jelly  may  be  kept  in  cool  weather  for  some  days  without 
change ;  but  in  open  vessels  it  soon  becomes  mouldy, 
especially  in  the  vicinity  of  flowering  plants.  "  Gelatine 
is  not  soluble  in  absolute  alcohol,  and  when  alcohol  is 
added  to  a  warm  and  strong  aqueous  solution,  the  gelatine 
separates  in  the  form  of  a  white  viscid  substance.  It  is 
insoluble  in  ether,  and  in  fixed  and  volatile  oils.  When 
common  gelatine,  glue  for  instance,  is  digested  in  alcohol, 
it  yields  a  little  fat  and  extractive  matter  to  that  solvent. 
When  jelly  is  immersed  in  alcohol,  it  contracts  very  con- 
siderably in  consequence  of  the  abstraction  of  water ;  it 
was  thus  that  Gfonner  applied  it  for  the  reduction  in  size 
of  the  impression  of  lithographic  prints ;  and,  on  the  other 
hand,  when  the  original  impression  was  taken  upon  con- 
tracted gelatine,  it  could  be  so  dilated  by  immersion  in 
water,  as  to  give  a  greatly  enlarged  impression  of  a  small 
print. ' ' — -Brande.  * 

Gelatine  is  soluble  in  all  dilute  acids,  in  which  respect 
it  differs  from  albumen.  When  treated  with  sulphuric 
acid,  leucine  and  gelatine  sugar  are  formed,  the  latter  sub- 
stance having  been  discovered  by  Braconnot.  One  part 
of  pulverised  glue  was  mixed  with  two  parts  of  concentrated 
sulphuric  acid ;  after  having  been  left  in  this  condition 
for  twenty-four  hours,  during  which  time  no  discoloration 
took  place,  eight  parts  of  water  were  added,  and  the  mix- 
ture boiled  for  five  hours,  the  water  being  renewed 
occasionally.  The  liquor  was  then  further  diluted,  and 
saturated  with  chalk,  then  filtered  and  evaporated,  when 
*  "  Manual  of  Chemistry."  By  William  Thomas  Brande,  F.R.S.,  &c. 


CHEMICAL    THEORY  OF  THE   TANNING  PROCESS.    13 

it  yielded  a  syrup  which,  at  the  end  of  a  month,  produced 
small  sweet  crystals.  These  were  afterwards  washed  with 
weak  alcohol  to  separate  the  adhering  syrup,  and  purified 
by  a  second  crystallisation.  Gelatine  sugar  requires  414 
parts  of  water  to  dissolve  it. 

Action  of  Tannic  Acid  on  Gelatine,  &c. — The  most 
delicate  test  for  the  presence  of  gelatine  is  tannic  acid, 
and  when  we  consider  that  a  cloudy  precipitate  is  produced 
by  this  vegetable  acid  in  a  solution  consisting  of  1  part 
gelatine  in  5,000  parts  of  water,  we  may  begin  to 
realise  its  powerful  influence  upon  the  skin  of  animals  in 
the  process  of  tanning.  When  a  piece  of  prepared  skin — 
that  is  skin  which  has  been  soaked  in  milk  of  lime  and 
freed  from  its  cuticle,  hair  and  other  extraneous  matters 
— is  immersed  in  a  solution  of  pure  tannin  (tannic  acid)  or 
an  infusion  of  any  astringent  vegetable  containing  tannin, 
such  as  oak  bark  or  gall  nuts,  and  allowed  to  remain 
therein  for  a  moderate  length  of  time,  the  whole  of  the 
tannin  combines  with  the  skin,  which  becomes  hardened 
and  insoluble  in  water,  and  is  absolutely  incapable  of 
putrefaction.  It  is,  in  fact,  leather,  and  is  almost  impene- 
trable to  water. 

The  characteristic  properties  of  tannin  are  astringency 
in  taste,  and  the  power  of  being  precipitated  from  its 
aqueous  solution  by  a  persalt  of  iron,  either  of  a  bluish- 
black,  or  a  dark  green  colour.  The  colour  of  the  pre- 
cipitate, formed  in  a  solution  of  tannin  by  permits  of 
iron,  has  been  made  the  basis  of  an  arrangement  of  the 
different  tannins  into  two  varieties,  distinguished  as  1, 
tannin  which  precipitates  iron  bluish-black,  and  2,  tannin 
which  precipitates  iron  green.  Upon  this  subject  Gmelin 
says : — 

"  On  the  validity  of  the  distinction  between  iron  blueing 
and  iron  greening  tannin,  several  views  have  been  put  for- 
ward, in  which,  however,  these  denominations  have  been 
understood  as  applying  to  two  groups  of  bodies.  If, 
according  to  Geiger,  water  containing  a  small  quantity  of 
alkali  be  gradually  added  to  a  ferric  salt  [as  persulphate 
of  iron],  which  has  been  turned  green  by  any  kind  of  iron 


14  LEATHER  MANUFACTURE. 

greening  tannin,  the  green  colour  changes  to  violet-black, 
the  tint  usually  produced  by  iron  blueing  tannin.  On 
adding  an  acid,  the  green  colour  is  restored.  According 
to  this  result,  the  difference  between  the  two  groups  might 
be  that  the  iron  blueing  tannin  is  less  rich  in  free  acid ; 
nevertheless,  it  reddens  litmus  more  strongly  than  the 
other  kinds  of  tannin.  It  appears  to  contain  \_qij.  to  be 
capable  of  yielding]  a  larger  proportion  of  gallic  acid, 
but  iron  blueing  tannin  is  not  converted  into  the  iron 

freening  kind  by  the  addition  of  gallic  acid  (Gmeliri). 
he  blue  or  green  reaction  is  by  no  means  an  infallible 
characteristic  of  the  species  of  tannic  acid,  since  bases 
colour  the  ferric  compounds  of  tannic  acid  blue,  and 
acids  change  the  blue  to  green.  With  ferric  acetate, 
the  iron  greening  acids  form  a  blue  compound ;  the  green 
compound  which  they  form  with  other  ferric  salts  is 
turned  blue  by  the  addition  of  a  sufficient  quantity  of 
acetate  of  lead,  either  neutral  or  basic,  and  even  by  a 
large  quantity  of  gelatine.  A  compound  of  iron  greening 
tannic  acid  with  lead  oxide,  is  turned  blue  by  ferric  sul- 
phate (persulphate  of  iron) ;  an  iron  greening  tannic  acid 
is  turned  blue  by  exposure  to  the  air,  in  contact  with  iron 
turnings.  But  the  colours  obtained  with  iron  greening 
tannic  acids  are  very  different  from  those  produced  by  the 
iron  blueing  acids,  and  the  two  cannot  be  converted  one 
into  the  other. 

"Thus,  catechu-tannic  acid  (obtained  by  exhausting 
catechu  with  a  small  quantity  of  water),  left  in  contact 
for  a  few  days  with  iron  filings,  assumes  a  dirty- greyish, 
not  a  blue-black  colour,  and  the  precipitate  does  not  turn 
green  when  treated  with  a  small  quantity  of  acetic  acid, 
but  dissolves  on  the  addition  of  a  larger  quantity,  and  is 
precipitated  a  purple-grey  on  the  addition  of  ammonia. 
The  iron  greening  tannic  acids  of  catechu,  kino,  alder, 
larch,  and  birch  bark,  and  of  tormentilla  root,  are  likewise 
incapable  of  yielding  a  good  ink.  The  extracts  of  iron 
greening  parts  of  plants  do  not  yield  pyro- gallic  acid  by 
dry  distillation,  unless  they  contain  gallic  acid  ready 
formed"  (St  en  house).  This  also  shows  the  incorrectness  of 


CHEMICAL    THEORY  OF  THE    TANNING  PROCESS.    15 

the  view  advanced  by  Heming,  who  regards  the  two 
groups  as  not  essentially  different  from  gallo-tannin,  and 
as  identical  therewith,  when  pure. 

Dr.  Lewis  was  the  first  to  attempt  a  chemical  analysis 
of  nut-galls,  about  the  middle  of  the  last  century,  and  he 
detected  in  them  a  substance  "which  coagulates  with 
isinglass,  and  blackens  the  salts  of  iron."  Seguin,  how- 
ever, is  believed  to  have  been  the  first  to  accurately  deter- 
mine the  nature  of  this  peculiar  action  upon  gelatine,  and 
also  upon  the  skins  of  animals,  and  the  term  tannin  was 
applied  by  him  to  this  principle  as  existing  in  a  variety 
of  vegetable  substances  employed  in  the  conversion  of 
skins  and  hides  into  leather.  Proust  was  the  first  who 
attempted  to  obtain  tannin  in  a  pure  and  separate  state, 
and  Sir  II.  Davy  determined  its  relative  quantity  in  a 
variety  of  tanning  materials.  It  was  not,  however,  until 
1834  that  Pelouze  discovered  a ,  method  of  separating 
tannic  acid  in  a  pure  state  (see  p.  43). 

Although  subsequent  researches  have  to  some  extent 
disproved  the  theory  which  Seguin  promulgated  at  a  time 
when  little  was  known  of  the  principles  of  tanning,  its 
reproduction  here  will  not  be  out  of  place^more  espe- 
cially as  it  will  enable  us  to  give  the  views  of  other 
chemists  of  eminence  concerning  the  weaker  points  of  hia 
theory. 

Seguin's  Theory  of  the  Art  of  Tanning.— 1.  The  skin, 
stripped  of  its  flesh,  is  a  substance  which  can  be  easily 
converted  by  a  convenient  process  into  an  animal  jelly, 
which,  concentrated  and  dried  in  the  air,  furnishes  glue. 

2.  A  solution  of  this  latter  substance  being  mixed  with 
an  infusion  of  tan,  an  insoluble  precipitate  is  formed,  and 
this  precipitate  is  not  susceptible  of  putrefaction. 

3.  The  solution  of  tan  is  composed  of  two  distinct  sub- 
stances ;  one  precipitates  the  glue,  and  is  the  true  tanning 
matter ;  the  other  precipitates  the  protosulphate  of  iron, 
without  precipitating  the  solution  of  glue,  and  produces 
only  the  disoxygenation  of  the  skin,  and  of  the  substance 
which  unites  the  hair  to  the  skin. 

4.  The  operation  of  tanning  is  not  a  simple  combination 


1 6  LEATHER  MANUFACTURE. 

of  the  skin  with  the  principle  which  precipitates  the  glue, 
but  a  combination  with  the  skin  disoxygenised  by  the 
substance  which  in  dissolution  in  the  tan  has  the  property 
of  precipitating  the  sulphate  of  iron.  Thus  all  substances 
to  be  used  to  tan  ought  to  have  the  properties  of  precipi- 
tating glue  and  sulphate  of  iron. 

5.  The  operation  of  tanning  consists,  first,  in  the  swell- 
ing of  the  skins  by  an  acid  principle ;  second,  a  disoxyge- 
nation  by  gallic  acid ;  third,  in  disoxygenating  the  skin  by 
the  same  principle ;  and  by  this  disoxygenation  it  is  in  a 
middle  state  between  glue  and  skin  ;  fourth,  in  combining 
it  by  this  disoxygenation. 

That  Seguin  was  in  error  in  supposing  that  gallic  acid 
entered  into  the  substance  of  the  skin  in  any  considerable 
proportion,  if  at  all,  there  cannot  be  the  least  doubt. 
Indeed  it  has  been  abundantly  proved  that  such  is  not  the 
case,  and  the  examination  of  the  exhausted  or  spent  tan 
liquors  detects  the  presence  of  this  acid  in  considerable 
proportion.  Dr.  Ure  says,  "  In  no  case  is  there  any  reason 
to  believe  that  the  gallic  acid  of  astringent  vegetables  is 
absorbed  in  the  process  of  making  leather ;  hence  Seguin' s 
theory  of  the  agency  of  that  substance  in  disoxygenating 
skin,  falls  to  the  ground."  Dussauce*  gives  the  following 
reasons  for  disagreeing  with  Seguin's  theory :  "  Whatever 
are  the  merits  of  Seguin,  and  the  services  he  has  rendered, 
we  cannot  but  expose  all  the  errors  of  the  above  theory. 
We  persist  in  looking  at  the  swelling  of  the  skin  as  an 
effect  less  chemical  than  mechanical,  which  is  principally 
due  to  the  interposition  of  the  water,  or  to  the  effect  of  the 
caloric  produced  by  fermentation.  Acids  and  alkalies  act 
only  as  a  means  of  preserving  the  skin  from  putrefaction ; 
afterwards  they  effect  a  chemical  action.  Thus  the  lime 
with  which  the  interior  of  the  skin  is  saturated,  notwith- 
standing all  the  washings,  forms  with  tannin  a  tannate  of 
lime,  which  takes  away  the  suppleness  of  the  leather,  and 
for  this  reason  it  is  that  the  lime  method  is  injurious.  It 

*  "  Treatise  on  the  Art  of  Tanning,"  &c.  Edited  from  Notes  and 
Documents  of  Sallerou,  Grouvelle,  Duval,  Dessables,  Labarraque,  Payen, 
Rene,  De  Fontenelle,  Malepyre,  &c.,  &c.  By  Professor  H.  Dussauce. 


CHEMICAL    THEORY  OF  THE   TANNING  PROCESS.    17 

is  not  the  same  with  acids.  Besides  preserving  the  skin 
from  putrefaction,  the  acetic  acid  produced  reacts  on  the 
fibrine,  softens  it,  and  transforms  it  partly  into  a  trans- 
parent jelly,  soluble  in  boiling  water,  and  combining  with 
the  tannin.  Besides  this  the  acid,  by  which  the  skin  is 
more  or  less  saturated,  precipitates  the  solution  of  tannin, 
and  fixes  a  larger  quantity  in  the  leather.  This  softening 
renders  the  swelling  very  easy.  However,  it  can  be  ope- 
rated without  these  means,  which  are  in  antagonism  with 
Seguin's  theory. 

* '  We  do  not  agree  with  Seguin  that  gallic  acid  is  the 
principal  and  indispensable  agent  in  tanning.  No  experi- 
ment has  demonstrated  the  durable  disoxygenation  which 
he  asserts,  and  which  is  impossible,  if  we  compare  the 
respective  constituents  of  gelatin  and  fibrin.  Thus  : — 

Fibrin  contains  19-615  per  cent,  of  oxygen. 
Gelatin     ,,         72-207        „  „ 

"  From  this  we  see  it  is  impossible  that  gallic  acid  dis- 
oxygenises  the  fibrine  and  transforms  it  into  glue,  whilst 
pure  gelatin  contains  nearly  one-half  more  of  oxygen.  If 
such  were  the  case,  gallic  acid  must  oxidise  instead  of  dis- 
oxygenising.  We  therefore  see  that  this  theory  is  inad- 
missible. Let  us  now  record  the  experiment : — 

Catechu  contains  from  48  to  54  per  cent,  of  tannin. 
Tea  „  34  to  40        „  „ 

Herb  Bennet     „  42  „  „ 

Squill  „  24  „  „ 

"  These  substances,  so  rich  in  tannin,  are  applied  with 
success  in  tanning  ;  while,  however,  they  do  not  contain  a 
particle  of  gallic  acid.  Seguin  does  not  mention  the  ex- 
tractive ;  however,  this  substance  has  some  action  in  the 
tanning,  and  according  to  Sir  H.  Davy  its  presence  is 
necessary  to  form  a  flexible  leather,  and  in  some  way  it 
may  take  the  place  of  tannin.  In  England,  where  tanning 
material  is  very  scarce,  they  have  used  the  decoction  of 
cicuta,  and  Schwerger  has  shown  by  analysis  that  100 
parts  of  fresh  leaves  contain  2*73  of  extractive,  without 

c 


IS  LEATHER  MANUFACTURE. 

tannin  or  gallic  acid.  To  resume,  we  regard  tanning  as, 
a  combination  of  five  principles  :  fibrin,  gelatin,  tannin 
extractive,  and  acid. 

"  1.  Gelatine  and  fibrin  are  transformed  into  a  jelly  by 
acetic  acid,  with  tannin,  extractive,  and  gallic  acid. 

"  2.  In  tanning,  the  epidermis  disappears,  and  no  por- 
tions of  the  skin  have  been  disoxygenated. 

"  3.  The  action  of  gallic  acid  is  similar  to  that  of  acetic 
acid,  and  its  presence  is  not  necessary  in  the  operation. 

"i  Extractive,  like  tannin,  unites  with  the  altered 
gelatin  and  fibrin,  and  renders  leather  flexible  and  firm. 
It  is  also  their  colouring  principle ;  thus  leather  tanned 
with  gall  is  pale,  that  with  oak  bark  brownish,  with 
catechu  reddish,  &c.  It  is  the  extractive  which  gives  the 
leather  a  brownish  colour,  without  rendering  it  insoluble 
in  boiling  water. 

"  5.  Lime  forms  with  tannin  a  tannate  of  lime,  which 
destroys  the  suppleness  of  the  leather,  and  renders  it  dry 
and  brittle. 

"  6.  Dried  skins,  well  tanned,  increase  in  weight  about 
33  per  cent.  This  increase  is  due  to  the  fixation  of  the 
tannin,  extractive,  gallic  acid,  (?)  and  a  little  water. 

"7.  In  saturated  infusions  there  is  less  extractive  than 
tannin,*  which  in  weak  solutions  predominates.  That  is 
the  reason  why  it  is  necessary  to  place  the  skins  at  first 
in  very  weak  infusions,  and  lastly  to  saturate  them  little 
by  little,  with  tannic  acid  and  extractive,  so  as  to  have  a 
complete  tanning  and  more  supple  leather. 

"  8.  By  presenting  to  strong  infusions,  the  leather  con- 
tains but  very  little  extractive,  and  is  tanned  only  on  two 
surfaces,  the  centre  containing  little,  so  that  the  leather 
obtained  is  hard  and  brittle. 

"  9.  Lastly,  gallic  acid  exercises  so  slight  influence  on 
tanning  that  Sir  H.  Davy  thinks  that  it  is  doubtful  if  oak 
bark  contains  any." 

The  above  observations,  taken  collectively  as  the  opinions 
of  Dussauce,  Malepyre,  Pay  en,  Rene,  Labarraque,  de  Fon- 
tenelle  and  others,  and  supporting  as  they  do  the  views  of 

*  Davy. 


CHEMICAL    THEORY  OF  THE   TANNING  PROCESS.     19 

that  distinguished  philosopher,  Sir  Humphry  Davy,  cannot 
fail  to  prove  instructive  to  those  who  desire  to  pursue  the 
art  of  tanning  upon  truly  scientific  principles.  While 
disagreeing  with  Seguin's  views  as  to  the  part  which  gallic 
acid  plays  in  the  process  of  tanning,  we  must  not  forget 
the  great  services  he  rendered  to  the  followers  of  the  tan- 
ning art  by  explaining  the  main  principles  upon  which  the 
art  is  based,  and  which,  prior  to  his  researches,  were  but 
little  understood. 

As  we  have  before  shown,  the  process  of  tanning  essen- 
tially consists  in  forming  a  chemical  combination  of  the 
coriurn,  or  true  skin  of  animals,  with  the  vegetable  astrin- 
gent principle  tannin.  If  skins  were  merely  dried — 
although  they  would  possess  a  certain  degree  of  hardness 
and  durability  while  in  that  state,  they  would,  when  sub- 
jected to  moisture,  undergo  putrefaction,  and  consequent 
speedy  destruction.  Again,  untanned  skins  are  pervious 
to  water,  and  therefore  cannot  be  used  for  the  many  pur- 
poses to  which  leather  is  so  extensively  applied.  When 
skins  are  tanned,  however,  not  only  is  their  chemical  con- 
stitution changed,  but  they  are  also  rendered  impermeable 
to  water,  besides  being  absolutely  unputrefiable.  More- 
over, during  the  combination  of  tannin  with  the  skin 
it  is  believed  that  vegetable  extractive  matter  from  the 
bark,  &c.,  also  enters  somewhat  largely  into  the  substance 
of  the  skin,  to  which,  no  doubt,  some  of  the  valuable  pro- 
perties of  leather  are  due.  Sir  H.  Davy  observes  upon  this 
subject : — 

"  When  skin  is  very  slowly  tanned  in  weak  solutions  of 
the  barks,  or  of  catechu,  it  combines  with  a  considerable 
proportion  of  extractive  matter ;  and  in  these  cases,  though 
the  increase  of  the  weight  of  the  skin  is  comparatively 
small,  yet  it  is  rendered  perfectly  insoluble  in  water, 
forming  a  soft,  but  at  the  same  time  a  strong,  leather. 
The  saturated  astringent  infusions  of  barks  contain  much 
less  extractive  matter  in  proportion  to  their  tannin  than 
the  weak  infusions ;  and  when  the  skin  is  quickly  tanned 
in  them  common  experience  shows  that  it  produces  leather 
less  durable  than  the  leather  slowly  formed.  Besides, 


20  LEATHER  MANUFACTURE. 

in  the  case  of  quick  tanning,  by  means  of  infusions  of 
barks,  a  quantity  of  vegetable  extractive  matter  is  lost 
to  the  manufacturer  which  might  have  been  made  to 
enter  into  the  composition  of  the  leather."  These  observa- 
tions show  that  there  is  sufficient  foundation  for  the  opinion 
of  the  workmen  concerning  what  is  technically  called  the 
feeding  of  leather,  in  the  slow  method  of  tanning ;  and 
though  the  processes  of  the  art  may  in  some  cases  be  pro- 
tracted for  an  unnecessary  length  of  time,  yet  in  general 
they  appear  to  have  arrived,  in  consequence  of  repeated 
practical  experiment,  at  a  degree  of  perfection  (in  the 
quality  of  the  leather)  which  cannot  be  very  far  exceeded 
by  any  elucidations  of  theory  that  have  yet  been  made 
known. 

It  must  be  confessed  that  the  old  tanners,  although  they 
may  be  said  to  have  worked  upon  the  rule-of-thumb  prin- 
ciple, often  had  for  their  guidance  those  useful  substitutes 
for  scientific  knowledge — good  common  sense  and  keen 
observation.  Hence  we  find  that  they  discovered,  in  prac- 
tice, that  hides  tanned  slowly  produced  the  best  leather, 
in  which  view  they  were  supported  by  Sir  Humphry 
Davy,  who  found  that  saturated  infusions  of  astringent 
barks  contained  much  less  extractive  matter  in  propor- 
tion to  their  tannin  than  weak  infusions.  Davy  further 
observes,  "  On  the  first  view  it  appears  singular  that  in 
those  cases  where  extractive  matter  forms  a  certain  portion 
of  the  leather,  the  increase  of  weight  is  less  than  when  the 
skin  is  combined  with  pure  tannin  ;  but  the  fact  is  easily 
accounted  for  when  we  consider  that  the  attraction  of  skin 
for  tannin  must  be  probably  weakened  by  its  union  with 
extractive  matter ;  and  whether  we  suppose  that  the  tannin 
and  extractive  matter  enter  together  in  combination  with 
the  matter  of  the  skin,  or  unite  with  separate  portions  of 
it,  still,  in  either  case,  the  primary  attraction  of  tannin  for 
the  skin  must  be  to  a  certain  extent  diminished." 

"  In  examining  astringent  vegetables,"  says  Davy, 
"  in  relation  to  their  powers  of  tanning  skin,  it  is  neces- 
sary to  take  into  account  not  only  the  quantity  they 
contain  of  the  substance  precipitable  by  gelatine,  but  like- 


CHEMICAL    THEORY  OF  THE   TANNING  PROCESS.    21 

wise  the  quantity  and  nature  of  the  extractive  matter; 
and  in  some  cases  of  comparison  it  is  essential  to  employ 
infusions  of  the  same  degree  of  concentration.  It  is  evident 
that  of  all  the  astringent  substances  which  have  been  as 
yet  examined,  catechu  is  that  which  contains  the  largest 
proportion  of  tannin  ;  and  supposing,  according  to  common 
estimation,  that  from  4  to  5  Ibs.  of  common  oak  bark  are 
required  to  produce  1  Ib.  of  leather,  it  appears  from  the 
various  synthetical  experiments  that  about  half  a  pound 
of  catechu  would  answer  the  same  purpose. " 

Mr.  Purkis  found  that  1  Ib.  of  Bombay  catechu  was 
equivalent  to  7  or  8  Ibs.  of  oak  bark ;  and  that,  allowing 
for  the  difference  in  the  composition  of  the  different  kinds 
of  leather,  1  Ib.  of  catechu,  for  the  common  uses  of  the 
tanner,  would  be  nearly  equal  to  2  J  Ibs.  of  galls,  to  7  Ibs.  of 
Leicester  willow,  to  lllbs.  of  Spanish  chestnut  bark,  to 
18  Ibs.  of  elm  bark,  to  21  Ibs.  of  common  willow  bark,  and 
to  3  Ibs.  of  sumac. 

Dr.  lire  remarks,*  "The  older  tanners,  who  prided 
themselves  on  producing  a  substantial  article,  were  so 
much  impressed  with  the  advantages  of  slowly  impreg- 
nating skin  with  astringent  matter  that  they  employed  no 
concentrated  infusion  (ooze)  in  their  pits,  but  stratified  tho 
skins  with  abundance  of  ground  bark,  and  covered  them 
with  soft  water,  knowing  that  its  active  principles  are  very 
soluble,  and  that,  by  being  gradually  extracted,  they  would 
penetrate  uniformly  the  whole  of  the  animal  fibres,  instead 
of  acting  chiefly  upon  the  surface  and  making  brittle 
leather,  as  the  strong  infusions  never  fail  to  do.  In  fact, 
100  Ibs.  of  skin,  quickly  tanned  in  a  strong  infusion  of 
bark,  produce  137 Ibs.  of  leather;  while  100 Ibs.,  slowly 
tanned  in  a  weak  infusion,  produce  only  117 Jibs.  The 
additional  19 Jibs,  weight  in  the  former  case  serve  merely 
to  swell  the  tanner's  bill,  while  they  deteriorate  the  leather 
and  cause  it  to  contain  much  less  of  the  textile  animal 
solid.  Leather  thus  highly  charged  with  tannin  is,  more- 
over, so  spongy  as  to  allow  moisture  to  pass  through  its 
pores,  to  the  great  discomfort  and  danger  of  persons  who 

*  "  Dictionary  of  Arts,  Manufactures,"  &c.    By  Andrew  Ure,  M.D. 


S3  LEATHER   MANUFACTURE. 

wear  shoes  made  of  it.  That  the  saving  of  time  and  the 
increase  of  product  are  temptations  strong  enough  to 
induce  many  modern  tanners  to  steep  their  skins  in  a 
succession  of  strong  infusions  of  bark  is  sufficiently  intel- 
ligible, but  that  any  shoemaker  should  be  so  ignorant  or 
so  foolish  as  to  proclaim  that  his  leather  is  made  by  a 
process  so  injurious  to  its  quality  is  unaccountably  stupid." 
During  the  process  of  tanning,  more  especially  by  the 
modern  system,  in  which  infusions  of  bark  and  other 
tanning  materials  are  used,  chemical  decomposition  of  a 
portion  of  the  tannin  takes  place  by  a  process  of  fermenta- 
tion, by  which  gallic  acid — a  useless  product  to  the  tanner 
— is  formed.  This  will  be  considered  in  the  chapter  on 
Gallic.  Fermentation,  and  the  various  remedies  for  its  pre- 
vention dulv  given. 


CHAPTER  n. 
THE  SKIN. 

The  Skin.— Stiucturc  of  the  Skin.— Mr.  Ashc's  Description  of  the  Skin.— 
Composition  of  the  Skin. 

The  Skin. — It  is  of  the  first  importance  to  the  tanner 
that  he  should  be  acquainted  with  the  anatomical  structure 
of  that  part  of  the  animal — the  skin — the  treatment  of 
which  constitutes  his  art.  This  knowledge  is  more  espe- 
cially necessary,  since  not  only  does  the  cuticle,  or  outer 
surface  of  tne  skin,  resist  the  action  of  the  tanning  prin- 
ciple, but  the  underlying  substance,  the  true  skin,  when 
brought  in  contact  with  tan,  or  tannin,  undergoes  a  defi- 
nite chemical  change,  by  which  its  whole  character  and 
properties  are  completely  altered. 

Structure  of  the  Skin.— The  skin  of  animals  consists  of 
two  distinct  layers,  which  are  thus  classified :  1 .  The 
Cuticle,  epidermis,  or  scarf  skin ;  and  2.  The  Cutis,  corium, 
or  true  skin  (cutis  vera).  The  cuticle  varies  in  thickness  in 
different  animals,  and  in  different  parts  of  the  body ;  it  is 
insoluble  in  water,  alcohol,  and  dilute  acids ;  strong  acids 
soften  it,  and  ultimately  dissolve  it,  while  solutions  of 
caustic  alkalies,  as  soda  and  potassa,  freely  dissolve  it, 
even  when  very  dilute.  The  cuticle  readily  absorbs  cer- 
tain colouring  matters,  which  impart  to  it  a  permanent 
dye.  Between  the  cuticle  and  the  corium  is  the  areolar 
tissue,  formerly  termed  the  rete  mucosum,  in  which  the 
roots  of  the  hair  are  embedded.  This  tissue  contains  the 
colouring  matter  which  gives  to  the  skin  its  characteristic 
tint,  and  which  is  much  influenced  by  the  action  of  light. 
"  The  black  skin  of  the  African,"  says  Brande,  "  the 
brown  of  the  Asiatic  and  American,  and  the  pinkish -white 


24  LEATHER  MANUFACTURE. 

of  the  European,  derive  their  colour  from  this  peculiar 
secretion  deposited  between  the  cutis  and  cuticle;  the 
nature  of  this  substance  has  not  been  chemically  investi- 
gated, but  it  has  been  ascertained,  in  regard  to  the  black  of 
the  negro,  that  it  admits  of  being  bleached  by  chlorine." 

The  cutis,  or  true  skin,  is  of  a  fibrous  texture,  almost 
wholly  soluble  when  boiled  in  water,  and  the  solution, 
when  cold,  forms  a  tremulous  jelly,  which  is  gelatine — the 
chief  constituent  of  the  cutis,  or  that  part  of  the  skin 
which,  when  submitted  to  the  action  of  tannic  acid,  consti- 
tutes tanned  leather,  or  more  properly,  tanned  skin. 

The  structure  and  functions  of  the  human  skin  are 
admirably  described  by  Mr.  Ashe  in  a  valuable  paper  upon 
this  subject ;  although  objection  may  be  taken  to  our 
having  chosen  this  author's  description  of  the  human  skin 
instead  of  giving  that  of  the  ox  or  other  inferior  animal, 
we  venture  to  suggest  that  for  the  purposes  of  the  tanner, 
who  practically  requires  merely  to  know  the  structure  of 
the  skin  and  its  functions  generally,  without  troubling  him- 
self about  the  comparative  anatomy  of  the  subject — the 
full  and  minute  description  given  by  Mr.  Ashe  will  enable 
him  to  comprehend  the  true  character  of  the  delicate 
fibrous  structure  of  the  cutis,  which,  when  separated  from 
its  cuticle,  hair,  and  fleshy  matters,  constitutes  the  pelt  or 
part  of  the  hide  to  be  tanned.  Moreover,  when  the  fibrous 
texture  of  the  unhaired  skin  is  thoroughly  understood,  the 
tanner  is  better  able  to  regulate  and  control  its  proper 
treatment  in  the  various  stages  of  the  several  processes 
which  constitute  the  art  of  tanning. 

Mr.  Ashe's  Description  of  the  Skin. — "  The  cutis,  or 
true  skin,  rests  upon  a  very  fine  interlaced  or  netted  struc- 
ture, called  the  areolar  tissue,  out  of  which,  if  we  may  so 
express  it,  the  granules  and  fibres  of  the  skin  are  formed. 
The  cuticle,  or  scarf  skin,  is  never  of  any  great  thickness 
in  any  animal,  but  the  true  skin  is  of  very  variable  thick- 
ness. In  the  whale  the  cutis  attains  the  thickness  of  about 
an  inch,  which  is  the  greatest  known  in  any  animal.  The 
cuticle  consists  of  several  layers  of  laminated  scales,  the 
laminated  form  being  best  marked  at  the  very  surface, 


THE  SKIN.  15 

where  the  scales  are  constantly  falling  off,  as  a  kind  of 
scarf,  and  are  as  constantly  being  renewed  from  below. 
These  scales  are  formed  by  the  flattening  out  of  granules, 
more  or  less  rounded,  which  is  the  form  assumed  by  the 
particles  of  the  cuticle  in  its  deeper  layers.  These  granules 
are  at  first  nucleated*  cells,  and  the  colouring  matter  of 
the  skin  resides  in  the  nuclei  ;  and  it  was  these  granules 
that  were  formerly  described  as  a  separate  layer,  under  the 
name  of  rcte  mucosum.  They  are  very  minute,  being 
about  -jtrW  Par^  °f  an  incn  ^n  diameter  at  first.  Being 
removed  from  below,  as  the  flattened  scales  are  removed 
from  above,  they  gradually  approach  the  surface,  and  as 
they  do  so  they  more  and  more  lose  the  granular  form,  and 
assume  the  scaly  character,  their  diameter  increasing 
accordingly  to  about  ^^  of  an  inch.  Into  the  epidermis, 
or  cuticle,  no  nerves  or  blood  vessels  penetrate,  and  it  is 
nourished  merely  by  the  transudationf  of  the  serum  of  the 
blood  through  the  walls  of  the  vessels  of  the  true  skin  and 
subcutaneous  areolar  tissue.  It  is  not  itself  sensitive,  but 
on  the  contrary,  serves  to  blunt  the  too  exquisite  sensation 
of  the  true  skin,  which  is  much  more  highly  organised, 
and  consists  of  two  kinds  of  tissue,  namely,  white  and 
yellow  fibres,  the  former  being  denser  and  more  resisting, 
and  being  therefore  present  in  greater  quantity  wherever 
resistance  is  most  needed,  as  in  the  palm  of  the  hand  and 
sole  of  the  foot  ;  while  the  yellow  fibres  are  a  highly  elastic 
tissue,  owing  to  their  minute  fibrilta  being  arranged  in 
interlacing  curves  ;  and  the  fibres  cross  each  other  repeat- 
edly, and  branch,  so  as  to  form  lozenge  -shaped  interstices, 
which  are  filled  up  principally  by  the  white  fibres.  The 
yellow  fibres  accordingly,  as  might  have  been  anticipated, 
exist  in  greater  abundance  where  elasticity  is  a  special 
requirement,  as  at  the  flexures  of  the  joints,  the  lips,  &c. 
The  uppermost  surface  of  the  cutis,  or  true  skin,  is  strangely 
uneven  and  irregular,  being  elevated  into  a  vast  number  of 
minute  papillae,  which  are  about  -p^  of  an  inch  in  height 
and  --  of  an  inch  in  diameter.  Minute  as  these  little 


*  From  nucleus,  a  body  round  which  anything  is  collected  or  deposited. 
1  Passing  through  as  vapour. 


26 


LEATHER  MANUFACTURE. 


)illae  are,  each  possesses  a  ramification  of  vascular  capil- 
ries,  and  of  nerve  fibres,  being,  in  fact,  the  essential 
agents  in  the  sense  of  touch,  for  that  is  the  function  of 
these  papillae.  The  skin  of  the  tongue  in  men  and  animals 
shows  the  papillae  larger  than  in  any  other  part  of  the 
body."  The  accompanying  illustration  (Fig.  1)  represents 

a  highly  magnified  view  of 
the  skin,  with  its  secreting 
glands  and  perspiratory 
ducts,  a  is  the  cuticle,  or 
scarf  skin  ;  b  the  areolar 
tissue,  and  c  the  cut  is,  or 
true  skin. 

"  The  true  skin  is  perfo- 
rated by  perspiratory  ducts 
(/),  and  when  the  hand  is 
warm  the  perspiration  may 
be  observed,  even  with  the 
naked  eye,  to  issue  from 
them,  forming  minute  shin- 
ing dots.  The  glands  (e)  by 
which  the  perspiration  is 
secreted,  are  seated  at  the  under  surface  of  the  true  skin, 
each  embedded  in  a  cavity  of  it.  These  glands  are  con- 
sequently to  be  regarded  as  true  excretory  organs,  re- 
moving from  the  blood  materials  that  are  no  longer 
wanted,  and  which,  if  retained,  would  be  injurious.  About 
2,500  of  these  ducts  are  found  in  the  square  inch  of 
the  skin. 

"  Another  kind  of  gland  is  also  formed  in  the  skin,  in 
connection  with  the  hairs,  and  engaged  in  their  nutrition ; 
these  glands  are  called  sebaceous  glands  (d) ;  the  ducts  of 
these  glands  are  not  spiral,  and  they  open  generally  into  the 
hair  follicles  or  pits  which  the  hair  grows  out  of,  situated 
in  the  subcutaneous  areolar  tissue  ;  these  glands  lubricate 
the  skin,  and  so  maintain  its  elasticity :  and  they  also 
eliminate  hydrocarbons  from  the  skin." 

It  will  be  seen  from  the  above  observations  that  the 
direction  of  the  secreted  fluids  of  the  true  skin  is  outward, 


Fig.  1, 


THE  SKIN.  vj 

or  in  the  direction  of  the  cuticle,  consequently  the  absorp- 
tion of  tanning  material  would  be  more  powerful  at  the 
flesh  side  than  at  the  grain  side  of  the  skin. 

Composition  of  the  Skin.— A  piece  of  fresh  skin,  freed 
on  its  internal  side  from  fat  and  cellular  tissue,  and  on  its 
external  side  from  the  epidermis  (cuticle)  and  the  mucous 
membrane  (areolar  tissue),  which  lies  between  the  epider- 
mis and  the  true  skin,  contains  about  43  per  cent,  of  solid 
matter,  the  remainder  being  water.  Of  the  solid  matter 
about  32  per  cent,  of  the  weight  of  the  humid  skin  is  the 
fibrous  and  cellular  tissue,  and  a  little  fatty  matter,  each 
of  which  is  insoluble  in  cold  water ;  To  per  cent,  is  unco- 
agulated  albumen.  About  1  per  cent,  is  a  variety  of 
extractive  matter,  soluble  in  water  and  alcohol,  and  7*5  per 
cent,  is  another  kind  of  extractive  matter,  soluble  in  water, 
but  insoluble  in  alcohol. —  Wcinholt. 

Nearly  the  whole  of  the  albumen  and  other  matters 
capable  of  being  dissolved  by  cold  water  may  be  separated 
by  digesting  the  skin  in  that  liquid.  When  the  washed 
skin  is  dried  and  digested  in  ether,  a  small  quantity  of 
fatty  matter  is  dissolved  out.  By  digestion  in  boiling 
water  the  greater  part  of  the  true  skin  becomes  altered  in 
properties  and  dissolved ;  only  some  vascular  and  nervous 
filaments,  with  a  little  fat,  remaining  undissolved,  and  the 
solution,  when  slowly  evaporated,  leaves  a  residue  of  gela- 
tine, or  glue. — Parnell.  According  to  Berzelius,  gelatine 
does  not  exist,  as  such,  in  the  living  body,  but  several  animal 
tissues,  such  as  skin,  cartilages,  tendons,  the  serous  mem- 
branes and  bones,  are  susceptible  of  being  converted  into  it 
by  the  action  of  boiling  water.  The  term  gelatinous  tissue 
is  commonly  used  to  designate  all  animal  tissues  which  are 
convertible  into  gelatine  by  such  a  process.  Dilute  acids 
and  alkalies  possess  the  property  of  converting  gelatinous 
tissues  into  gelatine  even  at  the  ordinary  temperature. 


CHAPTER  III. 

HIDES  AND    SKINS. 

Classification  of  the  Skins  of  Animals. — Condition  of  Hides  and  Skins. — 
Hides. — Native  Hides. — Dried  Hides. — Salted  Hides.— Dried  Salted 
Hides. — Selection  of  Hides. — Warbles. — Abusive  Treatment  of  Raw 
Hides. — Kips. — Buffalo  Hides. — Horse  Hides. — Ass  and  Mule  Hides. 
— Hippopotamus  Hides. — Calves'  Skins. — Sheep  Skins. — Lamb  Skins. 
— Goat  Skins.— Kid  Skins. — Hog  and  Pig  Skins. — Seal  Skins. — Deer 
Skins. — Porpoise  Skins. — Serpent  and  Crocodile  Skins. 

Classification  of  the  Skins  of  Animals.  —  These  are 
known,  commercially,  under  three  different  heads,  namely 
— 1.  Hides,  or  the  skins  of  the  larger  and  full-grown 
animals,  as  the  ox,  cow,  bull,  buffalo,  horse,  and  hippopo- 
tamus ;  2.  Kips,  or  the  skins  of  the  smaller  Indian 
animals  of  the  bovine  class  ;  and  3.  Skins,  as  those  of  the 
smaller  animals,  such  as  the  calf,  sheep,  goat,  deer,  &c. 
The  skins  which  are  most  extensively  used  in  the  manu- 
facture of  the  various  kinds  of  leather  are  those  of  the 
ox,  cow,  bull,  horse,  calf,  sheep,  goat,  kid,  pig,  deer,  seal, 
and  kips;  but  the  skins  of  crocodiles,  alligators,  and 
even  serpents  are  also  employed  for  making  certain  kinds 
of  fancy  leathers. 

Condition  of  Hides  and  Skins. — The  quality  of  hides 
and  skins  is  greatly  influenced  by  the  conditions  under 
which  the  animal  has  grown,  the  nature  of  its  food,  the 
variety  of  breed,  climate,  the  state  of  its  constitution,  its 
age,  and  the  time  of  year  at  which  it  has  been  slaughtered. 
The  hides  of  the  larger  oxen  form,  when  tanned,  a  stouter 
and  heavier  leather  than  those  of  cows,  especially  if  the 
latter  are  from  old  animals  or  from  those  which  have 
calved  several  times.  The  hides  of  bulls  are  of  coarser 
grain  and  thinner  in  the  back,  or  butt,  than  those  of  oxen 
and  heifers,  or  young  cows,  although  they  are  stouter  in 


HIDES  AND  SKINS.  29 

the  neck  and  certain  parts  of  the  belly.  Muspratt  says, 
"  Hides  of  animals  dying  in  a  state  of  disease  are  found  to 
be  much  inferior  to  those  of  healthy  ones  of  the  same 
class,  although  the  apparent  difference  is  not  very  marked 
before  tanning.  No  very  definite  criteria  are  known  to 
guide  the  purchaser  in  distinguishing  the  quality  of  hides 
and  skins.  If  the  hide  be  thin,  flabby,  soft,  and  will  not 
bear  handling,  then  such  a  one  will  not  make  good  leather ; 
but  should  it  present  the  opposite  qualities,  it  may  be  con- 
fidently expected  to  be  a  good  article.  It  has  been  remarked 
of  sheep  tnat  the  skin  gains  in  thickness  and  quality  con- 
siderably in  the  course  of  a  few  days  after  shearing." 

Hides. — Under  this  heading  are  included  the  skins  of 
oxen,  cows,  horses,  and  buffaloes.  The  hides  are  distin- 
guished as — 1.  Fresh,  or  green  hides,  or  those  which  come 
from  the  slaughter-houses  of  Great  Britain  ;  2.  Dried  hides, 
as  imported  from  Buenos  Ay  res,  the  Cape  of  Good  Hope, 
&c. ;  3.  Salted  hides,  those  which  come  from  Rio  Grande, 
River  Plate,  Australia,  &c. ;  and  4.  Dried  and  salted  hides, 
as  imported  from  Brazil,  Mauritius,  West  Indies,  and  other 
countries.  Although  the  hides  of  home  production  are  held 
in  the  highest  estimation,  the  imported  dried  and  salted 
hides,  when  subjected  to  certain  preparatory  processes  to 
bring  them  into  the  condition  of  green  hides,  form,  when 
tanned,  most  excellent  leather.  The  trouble  and  labour 
involved  in  softening  the  dried  skins  naturally  favours  a 
more  ready  market  for  those  of  home  production ;  neverthe- 
less we  import  enormous  quantities  of  hides  and  skins  from  all 
parts  of  the  world,  but  more  especially  from  South  America. 
The  vast  pampas  through  which  the  River  Plate  (or  Silver 
River)  and  its  tributaries  flow,  yield  boundless  pastures 
for  wild  or  partially  wild  oxen  and  horses,  which  have 
been  estimated  to  number  nearly  25,000,000.  Indeed,  the 
climate  of  this  district  seems  specially  suited  to  the  rearing 
of  cattle,  which  are  descended  from  the  tame  animals  first 
introduced  by  the  Spaniards  after  Columbus'  discovery. 
The  Buenos  Ayres  hides  obtained  from  the  most  southern 
states  are  considered  stouter  and  of  finer  texture  than  those 
of  Uruguay  or  Rio  Grande.  The  hides  from  the  more  teni- 


30  LEATHER   MANUFACTURE. 

perate  regions  are  salted,  and  exported  as  wet  salted,  while 
those  from  the  tropics  are  generally  dried  in  the  sun,  or 
salted  and  dried.  Dry  salted  hides  are  largely  exported 
from  Brazil,  Mauritius,  Madagascar,  &c. 

Native  Hides,  or  those  of  home  slaughter,  differ  greatly 
in  substance,  size,  and  texture ;  while  those  from  the  south 
of  England  yield  large  and  heavy  hides  of  fine  texture  and 
grain,  they  are  much  thinner  than  the  smaller  hides  of  the 
north  of  Scotland.  The  fattening  of  cattle  for  the  produc- 
tion of  good  beef,  to  suit  the  English  market,  renders  the 
hides,  although  of  great  size  and  weight,  considerably 
thinner  than  those  from  cattle  subjected  to  less  culture. 
The  hides  of  heifers  are  preferred  to  those  of  cows  which 
have  calved  several  times,  owing  to  the  latter  being  thinner 
and  of  poorer  substance.  Bull  hides  are  not  liked  by 
the  tanner,  owing  to  their  want  of  uniformity  in  sub- 
stance, being  thin  in  the  back  and  thick  at  the  shoulders 
and  the  surrounding  parts  called  offal.  Ox  hides  generally 
weigh  from  60  Ibs.*  to  120  Ibs.,  cow  hides  from  401bs.  to 
80  Ibs.,  and  kips  from  20  Ibs.  to  22  Ibs. 

Dried  Hides. — These  are  sometimes  called  "  flint " 
hides,  from  their  excessive  hardness.  It  is  well  known 
that  when  skins  are  dried  in  the  sun  they  become  nearly 
as  hard  as  horn,  and  when  in  this  condition,  they  require 
much  soaking,  rubbing,  and  beating  to  bring  them  to  the 
proper  state  for  treatment  in  the  lime  pits.  The  imported 
dried  hides  of  Buenos  Ayres,  Monte  Yideo,  and  other 
countries  are,  however,  extensively  used  by  the  tanner, 
and  from  them  leather  of  very  good  quality  is  produced. 

Salted  Hides. — The  salted  hides  from  South  America 
come  into  this  country  in  a  moist  condition,  a  large  quan- 
tity of  salt  being  stratified  between  each  hide.  Since  the 
salt,  however,  adds  considerably  to  the  weight  of  the  hides, 
it  is  usual  for  the  intending  purchaser,  when  inspecting 
them  at  the  docks  while  the  vessel  is  unloading,  to  turn 
them  over  before  having  them  weighed,  to  free  them 
as  far  as  possible  from  the  loose  salt ;  while  doing  so  he 

*  Hides  are  reckoned  small,  and  of  less  value  in  proportion,  when  they 
weigh  60  Ibs.  and  under.  Over  this  weight  they  rank  as  large  hides. 


HIDES  AND  SKINS.  31 

is  able  at  the  same  time  to  form  a  fai;  judgment  as  to 
their  condition.  These  hides  are  frequently  impaired  by 
the  barbarous  system  of  branding  adopted  by  the  South 
American  cattle  owners,  sometimes  as  many  as  half-a- 
dozen  brands  being  visible  on  a  single  hide.  These  im- 
pressions of  the  branding-iron  render  such  parts  of  the 
hide  useless  when  tanned,  whereby  the  manufacturer  neces- 
sarily suffers  loss.  Unsuccessful  attempts  have  been  made 
from  time  to  time  to  induce  cattle  owners  to  adopt  some 
less  brutal  and  injurious  system  of  marking  their  cattle. 
Probably  the  most  effectual  remedy  for  the  evil  would  be 
to  reject  all  such  heavily  branded  hides. 

Dried  Salted  Hides.— The  hides  from  Brazil,  Mauritius, 
West  Indies,  and  the  Cape  sometimes  come  into  the  market 
botli  dried  and  salted,  in  which  condition  they  are  more 
readily  brought  to  a  pliant  state  than  the  so-called  "  flint," 
or  dry  hides. 

Selection  of  Hides. — Although  judgment  based  upon 
practical  experience  is  the  only  reliable  guide  in  the  selec- 
tion of  hides  and  skins,  there  are  several  points  to  which 
special  attention  may  be  directed.  1.  The  hide  should  pre- 
sent the  appearance  of  having  been  well  flayed,  free  from 
cuts  or  gashes  produced  by  the  slaughterer's  knife,  and  pre- 
sent little  or  no  sign  of  decomposition.  2.  The  hide  should 
not  be  loose  and  flabby,  but  generally  firm  in  substance. 
3.  Besides  being  stout  in  the  back,  or  butt,  it  should  ex- 
hibit this  quality,  though  in  a  gradually  diminishing 
degree,  right  up  to  the  shoulder.  4.  The  hide  should  be 
free,  or  as  free  as  possible,  from  warbles  or  warble  marks, 
more  especially  if  to  be  used  in  the  preparation  of  harness, 
bucket,  or  hose  leather.  These  defects,  which  are  pro- 
duced by  the  larra,  or  grub,  of  the  bot,  or  gadfly  (oestrus 
bovis),  sometimes  cause  serious  injury  to  the  most  important 
portion  of  the  hide — the  back  ;  and  although  warbles  are 
of  less  consequence  in  the  production  of  sole  leather,  they 
would  be  fatal  to  leather  which  is  required  to  be  wind  or 
water  tight.  Since  the  subject  of  warbles  is  a  very  im- 
portant one,  and  has  received  much  attention  from  ento- 
mologists and  others,  it  may  be  well  to  consider  the  origin 


32  LEATHER  MANUFACTURE. 

and  nature  of  the  destructive  parasites  which  produce  the 
holes,  or  warbles,  in  the  hides  of  cattle. 

Warbles. — Some  persons  seem  to  have  entertained  the 
idea  that  the  grub  which  perforates  the  skin  of  oxen  is  de- 
veloped much  in  the  same  way  as  the  trichinae,  from  which 
the  devourers  of  uncooked  ham  and  bacon,  and  German 
sausage,  suffer — chiefly  in  Germany — in  the  form  of  disease 
known  as  trichinosis.  We  think,  however,  that  the  most 
reliable  evidence  is  in  favour  of  the  entomologists,  who  have 
universally  attributed  the  pest  to  the  gadfly,  an  insect 
which  is  well  known  to  haunt  the  meadows  in  which  cattle 
feed,  and  to  cause  the  animals  much  pain  and  suffering. 
It  appears  to  be  conclusive  that  the  gadfly  first  pierces  the 
skin  with  an  organ  termed  an  ovipositor — much  in  the  same 
way  that  a  wasp's  sting  is  introduced — and  that  in  the 
hole  thus  formed  an  egg  is  deposited,  which  after  a  time 
becomes  hatched.  The  existence  of  the  liberated  grub 
beneath  the  skin  causes  great  irritation,  and  an  open  sore 
is  established,  which  extends  as  the  larva  increases  in  size. 
When  it  has  become  fully  matured,  it  escapes  from  the 
hole,  and  falls  to  the  ground,  where  it  in  time  changes  to 
the  pupa,  or  chrysalis  state,  from  which,  in  the  following 
season,  the  pretty  but  dreaded  new-born  fly  emerges  to 
carry  on  the  war  with  the  bovine  race.  The  distinguished 
naturalist,  Sir  John  Lubbock,  says,  "  The  gadfly  deposits 
its  eggs  upon  the  bodies  of  animals,  and  the  grub  feeds 
inward  when  hatched."  Another  writer  in  The  World 
of  Insects  says  :  "  The  gadfly  at  certain  seasons  attacks 
oxen,  not  to  bite  and  suck  their  blood,  but  to  deposit  its 
eggs  in  the  hides  of  the  cattle — an  operation  which  is  not 
put  into  execution  without  occasioning  considerable  pain. 
The  circular  hole  thus  made  always  continues  open,  and 
increases  in  diameter  as  the  larva  increases  in  size,  which 
thus  enables  a  continual  supply  of  fresh  air  *  to  reach  the 

*  It  may  be  doubtful  whether  air  is  really  necessary  to  the  existence 
of  these  maggots,  since  the  trichinae,  tape  worms,  ascarides,  and  other 
well-known  parasites  seem  to  get  on  very  well  in  the  animal  system 
without  troubling  themselves  about  a  "breath  of  fresh  air."  An  animal 
that  thrives  upon  purulent  and  decomposing  matter  may  be  said  to  be  not 
very  particular  as  to  "  fresh  air." 


HIDES  AND  SKINS.  33 

insect.  But  although  they  torment  and  terrify  the  cattle 
during  the  time  of  ovipositing,  they  do  them  in  reality  no 
material  harm ;  indeed  tanners  prefer  hides  that  have 
the  greatest  number  of  hot  holes,  considering  them  the 
strongest  and  best,  which  indeed  they  are,  as  the  gadfly 
never  attacks  any  but  young  and  healthy  subjects."  This 
seems  an  extraordinary  statement,  and  one  which  the 
mind  cannot  readily  accept  as  based  upon  reasonable 
ground.  That  young  and  healthy  animals  should  be  pre- 
ferred by  the  anxious  parent  for  the  boarding  and  lodging 
of  her  progeny  is  quite  natural  and  to  be  applauded ;  but 
that  it  should  be  stated  that  tanners  prefer  perforated  to 
sound  hides  seems  inexplicable,  more  especially  as  it  is 
so  very  well  known  that  how  to  get  rid  of  warbles  has 
been  one  of  the  most  anxious  subjects  of  inquiry  connected 
with  the  trade  for  many  years. 

Referring  to  the  ox-bo  t  or  ox- gadfly,  another  writer  ob- 
serves— "  It  is  a  beautiful  insect,  not  quite  half-an-inch 
long,  and  thicker  in  proportion  than  the  horse-bot.  It 
has  brown,  unspotted  wings,  the  face  whitish,  the  crown 
of  the  head  brown,  the  thorax  black,  the  abdomen  whitish, 
with  a  broad  black  band  round  the  middle,  and  yellow 
hairs  at  the  extremity,  where  also  the  female  has  an  ovi- 
positor— a  remarkable  organ,  formed  of  a  horny  substance, 
consisting  of  four  tubes,  retractile  within  one  another,  like 
the  pieces  of  a  telescope,  and  the  last  of  them  terminating 
in  five  points,  three  of  which  are  longer  than  the  others, 
and  hooked.  By  means  of  this  organ,  a  small  round  hole 
is  pierced  in  the  hide  of  an  ox's  back,  in  which  an  egg  is 
deposited.  The  fly  is  very  quick  in  depositing  her  egg — 
not  remaining  on  the  back  of  the  animal  more  than  a  few 
seconds.  Cattle  exhibit  great  alarm  and  excitement  at 
the  presence  of  the  gadfly,  and  rush  wildly  about  with 
head  stretched  forward,  and  tail  stuck  out,  to  escape  from 
their  tormentor.  The  further  injury  done  by  this  insect 
is  not,  however,  usually  great,  the  larva — a  little  pearl- 
white  maggot  feeding  upon  the  juices  of  the  skin — caus- 
ing a  swelling,  called  a  icarble,  forming  a  sort  of  sac, 
within  which  it  lives  and  grows  amidst  a  kind  of  purulent 

D 


34  LEATHER  MANUFACTURE. 

matter  suited  to  its  appetite,  and  from  wliich  it  usually 
emerges,  leaving  a  small  sore ;  and,  like  the  horse-bot, 
undergoes  its  further  transformation  in  the  ground." 
Again,  Miss  Eleanor  A.  Ormerod,  who  had  worked  assidu- 
ously with  the  farmers  in  their  efforts  to  diminish  the 
injuries  caused  by  insects  to  their  crops,  writes:  "The 
oestrus  bovis  is  a  largish  two-winged  fly,  and  the  female 
lays  her  eggs  on  the  backs  of  horned  cattle.  The  maggots 
from  these,  by  feeding  on  the  flesh,  cause  tumours,  with 
an  opening  at  which  orifice  the  tail  end  of  the  maggot  is 
usually  exposed.  When  full  fed,  the  larva,  or  maggot, 
drags  itself  out  of  the  tumour  and  falls  to  the  ground, 
where  it  changes  to  the  pupa  or  chrysalis  state,  from  which 
in  due  time  the  rather  handsome  fly  emerges." 

The  above  observations  clearly  prove  the  origin  of 
warbles,  and  when  it  is  borne  in  mind  that,  besides  the 
positive  injury  done  to  the  hide,  the  animal  must  suffer 
great  and  continual  torture,  it  would  be  well  if  our  agri- 
cultural chemists  and  scientific  farmers  were  to  devote 
special  attention  to  the  subject,  with  a  view  to  discover 
some  means  of  rendering  the  skin  of  young  cattle  less 
attractive  to  the  gadfly.  This  might  be  accomplished, 
possibly,  by  brushing  over  that  part  of  the  skin  (the  back) 
which  is  generally  selected  as  the  depository  of  the  gad- 
fly's eggs,  some  oil,  or  solution  of  such  substances  as 
are  known  to  be  objectionable  to  insects,  but  harmless  to 
the  animals  themselves.  It  is  well  known,  for  example, 
that  the  smell  of  the  oil  of  birch  is  much  disliked  by  most 
insects,  as  also  is  creosote,  or  water  impregnated  with  it. 
Again,  powerful  bitters,  as  wormwood,  quassia,  and  aloes, 
are  repugnant  to  some  species  of  insects.  If,  therefore, 
during  that  period  of  the  year  when  the  gadfly  makes  its 
appearance,  the  backs  of  cattle  were  brushed  over  with  one 
or  other  of  these  agents,  is  it  not  probable  that  the  fly, 
recognising  a  foreign  flavour  or  odour  upon  the  skin  of  the 
animal,  would  abandon  it  and  fly  from  beast  to  beast  in 
search  of  one  more  suited  to  its  purpose  ?  Doubtless  the 
gadflies  emerge  from  the  shell  of  the  chrysalis  with  toler- 
able regularity  as  to  time,  in  which  case  the  appearance  of 


HIDES  AND  SKINS.  35 

the  first  insect  of  the  season  would  be  a  signal  for  the 
application  of  any  agent  which  it  was  desired  to  try  with  a 
view  to  determine  whether  a  remedy  for  warbles  could  bo 
found  in  the  direction  we  have  indicated. 

Abusive  Treatment  of  Haw  Hides.— Ordinary  care- 
lessness and  even  rough  usage,  of  a  raw  material  so  difficult 
to  handle  as  the  hide  of  such  a  large  animal  as  the  ox,  can 
neither  be  wondered  at  nor  prevented,  but  apart  from  this, 
hides  are  too  often  abused,  in  various  ways,  to  such  a  degree 
as  greatly  to  reduce  their  value  to  the  tanner.  Some  years 
ago  M.  H.  Lange,  a  Cordovan  leather  tanner,  at  a  meeting 
of  the  trade  at  Oschatz,  exposed  the  abuses  to  which  hides 
were  subject  before  they  fell  into  the  hands  of  the  tanner; 
and  since  his  observations  are  applicable  to  all  times  and 
places,  their  reproduction  here  will  doubtless  be  acceptable 
to  our  readers. 

"  M.  Lange  expressed  his  regret  that  in  the  prepara- 
tion of  the  hide  for  trade  purposes,  raw  hides  and  skins 
laboured  under  great  disadvantages,  owing  to  the  farmers' 
and  butchers'  handling,  inasmuch  as  this  was  not  carefully 
done  with  a  view  to  the  future  operations  to  bo  undergone 
by  the  raw  material.  The  bark  and  white  tanners  present 
at  the  meeting,  also  gave  expression  to  the  united  wish 
that  through  making  known  the  manipulations  which 
experience  has  proved  to  be  the  most  simple  and  at  the 
same  time  the  most  efficacious,  hides  or  skins  may  be 
delivered  in  a  condition  perfectly  suitable  to  the  process  of 
manufacture,  and  the  evils  specified  may  hereafter  be  done 
away  with  as  far  as  possible.  It  too  often  happens  that 
hides  and  skins  of  slaughtered  animals,  as  of  those  that 
have  died  from  natural  causes,  are  not  at  once  taken  off, 
but  left  for  days  on  the  carcase.  This  is  in  the  highest 
degree  detrimental  to  the  hides,  as  they  acquire  thin  and 
defective  spots  through  decomposition  going  on  in  the 
carcase,  or  the  worms  which  are  forming  in  the  interior  of 
the  animal  [query]  work  destructively  upon  the  hides. 

"  Great  damage  is  also  caused,  although  not  of  so  serious 
a  nature,  if,  in  flaying,  the  work  is  not  done  with  all  due 
care.  The  bits  of  flesh  and  fat,  which  are  too  often  allowed 


36  LEATHER  MANUFACTURE. 

to  remain  adhering  to  the  hides  and  skins,  become  at  once 
decayed  and  communicate  decay  to  the  skin,  which  is 
injured  or  eaten  away  in  spots,  becoming  consequently, 
and  subsequently,  very  thin,  or  even  worn  into  holes.  Such 
damage  is  noticeable  more  especially  after  manufacture, 
when  the  leather  is  found  bad  in  appearance  or  pitted 
with  dark  spots,  as  in  the  case  of  coloured  leather.  Leaving 
these  defects  out  of  the  question,  the  suppleness  and  dura- 
bility of  the  leather  itself  will  be  injuriously  affected  if  the 
skins  are  not  suitably  and  carefully  treated  in  drying  and 
hanging  up,  by  the  premature  shrinking  and  imperfect 
drying  of  the  material.  As  evidence  that  the  evils  just 
mentioned,  arising  from  improper  treatment,  are  of  more 
importance  than  is  generally  thought,  M.  Lange  states 
that  the  sheepskins  received  in  the  summer  season  often 
yield  barely  one-third  of  the  material  perfectly  adapted  to 
the  manufacture  of  imitation  Morocco  leather. 

"  In  view  of  these  evils,  and  in  order  to  promote  the 
interests  of  the  leather  trade,  the  following  points  are  to 
be  urgently  recommended  to  the  slaughterers  in  flaying 
hides  and  skins  : — 

"1.  Immediately  after  the  death  of  the  animal  the  hide 
or  skin  should  be  carefully  taken  off. 

"  2.  The  fleshy  or  fatty  portions  still  adhering  to  the 
skin  should  be  detached,  down  to  the  smallest  pieces. 

"3.  The  hide  should,  without  the  least  delay,  be  hung 
up  in  a  very  airy  place,  and  one  not  exposed  to  damp,  with 
the  hair  side  inward,  so  that  the  draught  of  air  may  play 
upon  the  entire  length  of  the  flesh  side  of  the  hide. 

"4.  In  order  to  prevent  the  hide  from  shrinking,  the  head 
and  tail  ends  should  be  stretched  out  and  nailed  to  the  pole. 

"  5.  The  hoofs  and  legs  should  be  spread  with  skewers 
on  both  sides. 

"  6.  The  flaying  of  the  hide  should  not  be  entrusted  to 
inexperienced  persons ;  for  unless  a  certain  dexterity  is 
brought  into  operation,  the  value  of  the  skin  will  be  con- 
siderably lessened.  Only  by  observing  these  directions, 
can  the  skins  and  hides  be  properly  dried  and  delivered 
free  from  defects,  suitable  for  valuable  use.  The  benefits 


HIDES  AND  SKINS.  37 

that  will  accrue  to  the  whole  leather  trade  by  following 
such  a  course  cannot  be  rated  too  highly,  for  not  only  will  it 
secure  a  serviceable  material  to  manufacturers,  but  also  a 
large  quantity  of  hides  and  skins  will  be  saved  from 
destruction,  and  the  market  will  be  better  and  more  fully 
supplied.  A  further  consequence  will  also  be  that  a  better 
manufactured  article  will  be  produced  and  lower  prices 
established." — Dussauce's  Treatise. 

A  few  years  ago  Mr.  George  Middleton,  manager  of 
the  Midland  Counties'  Butchers'  Hide,  Skin,  &c.,  Com- 
pany (Limited),  suggested  the  plan  of  issuing  cheques  to 
slaughtermen,  entitling  them  to  a  reward  of  sixpence  for 
each  hide  taken  by  the  company  flayed  to  its  satisfaction. 
In  addition  to  this,  the  master  butchers  agreed  to  give  an 
extra  sixpence  per  hide,  as  a  reward  for  careful  flaying, 
thus  giving  the  slaughtermen  one  shilling  per  hide  for 
performing  their  work  with  extra,  that  is  proper,  care. 

Kips,  or  skins  of  the  younger  and  smaller  animals,  are 
largely  imported  from  the  East  Indies,  the  Cape,  Australia, 
North  and  South  America,  and  elsewhere.  From  the  East 
Indies  they  arrive  either  dry,  dry  salted,  or  brined — that 
is,  simply  salted.  The  E.  I.  kips  are  the  skins  of  a  small 
breed  of  oxen,  and  being  derived  from  full-grown  animals 
they  are  in  reality  hides.  Besides  being  imported  in  either 
of  the  above  conditions,  a  large  quantity  reach  our  market 
in  the  tanned  state.  The  importation  of  E.  I.  kips  amounts 
to  millions  of  skins  annually.  Kips  are  also  imported 
from  the  countries  surrounding  the  Baltic,  but  these 
are  generally  obtained  from  animals  slaughtered  when 
young,  and  therefore  are  more  of  the  character  of  skins 
than  hides.  The  smaller  and  inferior  varieties  of  kips 
and  calfskins  are  tanned  for  the  purposes  of  the  book- 
binder and  glover,  and  also  in  the  preparation  of 
leather  for  uppers  of  the  lighter  kinds  of  boots  and 
shoes. 

Buffalo  Hides. — These  are  imported  from  various  parts 
of  the  East  Indies — as  Bombay,  Calcutta,  Batavia,  Kur- 
rachee,  &c.  These  hides  make  an  inferior  kind  of  sole 
leather,  and  are  tanned  in  the  same  way  as  ox  hides.  For 


38  LEATHER  MANUFACTURE. 

certain  purposes,  however,  they  are  tanned  in  a  peculiar 
manner,  and  then  form  what  is  known  as  luff,  or  belt 
leather,  which  possesses  superior  strength  to  the  same  article 
prepared  from  cow  hides.  The  annual  importations  have 
sometimes  amounted  to  upwards  of  300,000  hides. 

Horse  Hides. — The  best  horse  hides  are  those  which 
are  imported  from  the  River  Plate,  Rio  Grande,  and  other 
parts  of  South  America.  The  wild  horses  of  the  pampas, 
which  are  captured  and  slaughtered  chiefly  for  the  hides 
and  fat,  furnish  a  vast  supply  of  hides,  which  are  greatly 
superior  to  those  of  our  own  market,  which  are  generally 
from  old  and  worn-out  animals.  The  skin  of  the  horse  is 
much  inferior  to  that  of  the  ox,  or  even  cow,  as  to  strength, 
texture,  and  thickness,  and  is  therefore  not  suitable  for 
making  sole  leather ;  a  small  portion  of  the  back,  or  butt, 
nearest  the  animal's  rump,  however,  is  generally  cut  away, 
and  when  tanned  is  employed  for  upper  leather  ("  crap  "). 
The  better  qualities  of  horse  hides  are  tanned  for  uppers 
of  boots  and  shoes,  but  the  chief  purpose  to  which  they 
are  applied  is  in  making  Cordovan,  or  enamelled  leather. 
For  this  purpose  the  pelts  are  split  by  machinery,  which 
reduces  them  to  any  required  thinness.  These  hides  are 
also  tawed,  or  alumed,  and  converted  into  white  leather 
for  workmen's  aprons,  for  the  thongs  of  common  whips, 
and  other  useful  purposes. 

Ass  and  Mule  Hides. — When  tanned,  these  hides  form 
what  is  known  as  Shagreen,  or  Shagrin. 

Hippopotamus  Hides. — Only  a  limited  number  of  these 
skins  come  into  the  market,  being  imported  from  the  south 
of  Africa.  They  are  of  remarkable  thickness,  and  when 
tanned  are  exceedingly  hard.  The  principal  purposes  to 
which  the  tanned  hides  are  applied  is  for  implements  used 
in  washing  and  bleaching  cotton  and  linen  goods,  and  for 
making  circular  "buffs"  for  polishing  brass  and  other 
metals.  "Walrus  hides  are  also  used,  when  tanned,  for 
similar  purposes. 

Calves'  Skins,  of  home  produce,  are  of  very  superior 
quality,  and,  when  tanned  with  oak  bark,  produce  a 
leather  which  is  very  extensively  used  for  the  uppers  of 


HIDES  AND  SKINS.  39 

shoes  and  for  boot  fronts.  In  France,  which  is  famous  for 
the  excellence  of  its  calf-skin  leather,  the  calves  are 
slaughtered  when  about  ti ve  or  six  months  old. 

Sheep  Skins. — The  supply  of  sheep  skins  in  the  home 
market  is  very  extensive,  and  besides  this  source  of  supply 
an  immense  number  are  imported  from  South  America,  the 
Cape,  Australia,  and  many  other  countries :  a  very  con- 
siderable proportion  come  to  us  in  the  tanned  state. 
Although  sheep  skins  produce  but  a  very  weak,  spongy 
leather,  they  are  applied  to  a  great  variety  of  purposes. 
When  tanned  with  bark,  they  constitute  baziis,  and  are 
used  for  making  slippers,  and  also  as  bellows-leather; 
when  tawed,  or  prepared  with  alum  and  salt,  they  form 
what  is  termed  white  leather,  which  is  much  used  by  drug- 
gists, and  also  for  workmen's  aprons.  Sheep  skins  are  very 
often  subjected  to  the  operation  called  splitting,  when  the 
grain  side  is  tanned  with  sumac,  and  dyed,  and  is  after- 
wards worked  up  as  imitation  morocco,  roan,  or  skiver,  into 
covers  for  pocket-books,  for  hat  linings,  &c.  The  flesh  side 
is  converted  into  white  leather  for  druggists'  use,  or  into 
chamois,  or  shammy  leather  ;  for  the  former,  however,  lamb 
skins  are  most  generally  employed.  Sheep  skins  are  some- 
times tanned  with  the  wool  attached,  and  converted  into 
mats ;  or  tawed,  and  made  into  housings.  For  these  pur- 
poses the  best  skins  are  selected,  and  those  with  the  longest 
and  most  beautiful  fleece  are  chosen  by  preference. 

Lambs'  Skins  are  very  extensively  used  in  the  prepara- 
tion of  leather  by  the  process  of  tawing,  for  glove-making,  as 
a  substitute  for  kid  leather,  and  for  various  other  purposes. 
Besides  the  very  large  number  produced  in  this  country, 
great  quantities  of  lambs'  skins  are  annually  imported. 
There  is  a  great  difference  in  the  quality  of  these 
skins ;  those  from  the  animals  slaughtered  shortly  after 
birth  possess  an  exceedingly  fine  grain  and  are  sus- 
ceptible of  a  very  uniform  dye — an  important  feature  in 
skins  used  for  ladies'  gloves.  This  extreme  delicacy  of 
texture  is  retained  by  the  skin  of  lambs  until  after  they 
are  a  month  old,  from  which  period  they  gradually  lose  it. 
In  the  south  of  France  and  in  Italy  considerable  numbers 


40  LEATHER  MANUFACTURE. 

of  lambs  are  killed  averaging  four  weeks  old ;  leather  pre- 
pared from  these  skins  is  largely  used  for  "  kid  "  gloves. 

Goat  Skins. — A  very  extensive  trade  is  carried  on  in 
Great  Britain  and  Ireland  in  these  skins,  and  also  in  the 
tanned  and  tawed  leather  produced  from  them.  In 
Ireland  a  large  number  of  skins  of  native  produce  are 
used,  but  Great  Britain  is  supplied  chiefly  by  imports 
from  Switzerland,  and  the  Yalley  of  the  Rhine,  and  also 
from  India  and  the  Cape  of  Good  Hope,  from  which 
latter  places  they  are  imported  in  the  dry  state.  Millions 
of  these  skins,  however,  come  into  the  British  market 
already  tanned  and  tawed  from  these  countries.  The  Swiss 
goat  skins  are  most  highly  esteemed,  owing  to  the  very 
line,  close  and  uniform  texture  of  the  grain,  which  enables 
the  dyer  to  impart  a  brilliant  and  permanent  colour ;  the 
leather  prepared  from  Swiss  skins  is  said  to  be  stronger 
and  more  durable  than  any  other  manufactured  from  goat 
skins.  A  very  considerable  number  of  these  skins  are 
annually  converted  into  morocco  leather  for  various  uses 
in  the  different  branches  of  the  trade.  The  goat  skin 
tanned  and  dyed  on  the  grain  side  constitutes  true  morocco 
leather.  Mogadore  skins  are  made  into  a  kind  of  black 
morocco,  called  Cordovan,  in  consequence  of  the  first  sup- 
plies of  the  article  being  obtained  from  Spain  and  Cordova, 
where  the  Moors  originally  brought  the  manufacture  to 
great  perfection.  The  sound  skins  which  arrive  from  the 
Cape  of  Good  Hope,  are  much  larger  and  superior  in 
strength  and  thickness  to  any  other  variety.  East  India 
skins  are  small  and  light,  and  are  generally  converted  into 
chrome  leather  chiefly  used  for  ladies'  shoes.  Those 
from  Mexico,  known  in  the  American  market  as  Tampico 
skins,  bear  a  very  high  character.  Compared  with  sheep 
skins,  those  of  goats  are  much  superior  in  texture, 
strength,  and  durability.  Goat  skins  are  occasionally 
prepared  so  as  to  imitate  chamois  leather,  and  applied  to 
most  purposes  to  which  the  latter  is  adapted ;  and  like- 
wise with  the  hair  on,  and  used  for  matting. — Muspratt. 

Kid  Skins,  converted  into  leather  by  the  process  of 
tawing,  are  very  extensively  used  in  the  manufacture  of 


HIDES  AND  SKINS.  41 

gloves,  and  also  for  slippers,  or  light  shoes ;  by  druggists 
for  covering  the  corks  of  bottles,  and  for  other  useful 
purposes.  The  kid  skins  of  France — from  which  the 
famous  "  French  kid "  gloves  are  made — have  always 
been  held  in  high  estimation,  as  also  are  those  of  Ireland. 
After  the  animal  begins  to  feed  upon  herbage,  the 
skin  loses  in  delicacy  of  texture,  and  therefore  becomes 
unsuited  for  the  finest  gloves.  There  can  be  no  doubt 
whatever  that  from  the  time  the  young  animal  ceases  to 
derive  its  sustenance  from  the  mother,  and  feeds  upon 
vegetable  substances,  a  greater  degree  of  solidity  and 
firmness  of  texture  is  acquired  by  the  skin,  as  also  by  all 
other  parts  of  the  body,  and  as  a  consequence  the  elasticity 
and  extreme  fineness  "and  delicacy  in  texture  of  the  skin 
gradually  become  deteriorated. 

Hog  and  Pig  Skins. — The  practice  of  skinning  swine 
is  carried  on  in  Scotland,  and  also  on  the  Continent,  and 
the  skins,  when  tanned,  form  a  very  light  and  porous,  but 
still  very  tough  and  durable  leather,  which  is  extensively 
used  by  harness  makers,  and  also  for  the  seats  of  saddles. 
On  the  Continent  the  hide  is  dressed  with  the  hair  on,  and 
is  employed  for  covering  portmanteaus,  knapsacks,  &c. 
Pig  skin  is  also  used  for  leather  breeches,  but  not  to  such 
an  extent  as  formerly. 

Seal  Skins.— These  valuable  skins  are  imported  into 
this  country  in  very  considerable  quantities,  from  British 
North  America,  Newfoundland,  the  United  States,  the 
AVhale  Fisheries,  Norway,  the  Cape  of  Good  Hope,  and 
other  localities.  The  skin  of  the  seal  is  light,  and  of  very 
close  texture,  and  when  properly  tanned  is  considered  to 
produce  a  leather  of  greater  strength  in  proportion  to  its 
weight  than  any  other  kind  of  leather.  Seal  skins  are 
commonly  made  into  black  enamelled  leather,  for  ladies' 
shoes  and  boots,  and  the  stouter  varieties  are  used  for  the 
uppers  of  hunting  and  riding  boots,  knapsacks,  &c.  Seal 
skins  are  frequently  merely  dressed,  with  the  fur  on,  for 
ladies'  jackets  and  muffs,  and  various  articles  of  clothing, 
as  waistcoats,  caps,  &c. 

Deer  Skins  are  much  used  for  making  gloves  and  cha- 


42  LEATHER  MANUFACTURE. 

mois  leather,  and  are  prepared  by  the  tawing  process,  in 
the  same  manner  as  sheep  and  goat  skins.  The  chief 
manufacture  in  connection  with  deer  skins  is  carried  on  in 
the  United  States,  and  is  comparatively  unimportant  in 
this  country. 

Porpoise  Skins. — These  skins  are  now  being  much 
used  for  uppers  of  boots,  for  which  purpose  they  are  admi- 
rably suited,  since,  when  tanned,  they  yield  a  very  supple 
and  durable  leather.  Round  and  flat  laces  prepared  from 
these  skins  are  exceedingly  tough  and  strong.  In  Canada 
the  skins  of  the  white  porpoise  have  been  tanned  into 
leather,  which  is  said  to  be  soft,  strong,  and  of  a  beautiful 
finish. 

Serpent  and  Crocodile  Skins. — During  the  past  few 
years  specimens  of  tanned  serpent  skins  have  entered  the 
market,  as  also  those  of  the  crocodile  and  alligator,  and 
at  the  period  at  which  we  are  writing,  reticules,  purses, 
and  bags  formed  of  crocodile  and  alligator  skins  are  freely 
exposed  for  sale.  Indeed,  so  great. is  the  demand  for  this 
variety  of  ornamental  leather  that  close  imitations  of  the 
various  skins  are  produced  by  means  of  the  electrotype 
process.  (See  page  432.) 


CHAPTER  IV. 
TANNIN  OR  TANNIC  ACID. 

Tannin  or  Tannic  Acid. — Preparation  of  Tannic  Acid.  Pelonze's  Proces*. 
— Bcrzelius'  Process. — Bouillon  -  Legrange'  s  Process. — M  erat-Gui  I  lot'i 
Process.— Diz6's  Process.— Deyeux's  Process.— Proust's  Process. — 
Serturner's  Process. — Sobering' s  Process. — Badvil  and  Licnders' 
Process. — MM.  Coez's  Process. — Koh'rausch's  Process. — Properties 
of  Tannic  Acid. — Parnell's  Views. — Pure  Tannic  Acid. — Reactions 
of  Tannic  Acid. — Table  of  the  Percentage  of  Tannin  in  Vegetable 
Substances. — Morfit's  Observations. — Artificial  Tannin. 

Tannin,  or  Tannic  Acid.  —  This  powerful  astringent 
vegetable  principle,  which  is  also  known  by  the  names  of 
Tan  and  Gallo-tannic  acid,  exists  in  those  excrescences  called 
Gall  nuts,  which  are  found  upon  certain  varieties  of  oak, 
and  some  other  plants,  as  the  Tamarisk.  It  also  occurs  in 
a  great  number  of  trees  and  plants.  Galls  are  formed  by 
the  female  of  the  insect  Cynips  (or  Diplolepsis)  Gallte  tinc- 
tonim,  piercing  the  buds  of  a  species  of  oak  named  Querctts 
itifcctoria,  and  there  depositing  its  eggs.  These  producing 
irritation,  cause  the  juices  of  the  plant  to  flow  towards 
the  wound,  and  the  subsequent  enlargement  of  the  part, 
in  the  form  of  a  vegetable  tumour,  or  gall,  round  the 
larva.  This  grub,  when  fully  developed,  escapes  by  a 
hole  which  it  perforates  in  the  gall.  The  Quercus  infcctoria 
is  the  principal  species  of  oak  which  yields  the  nut-galls  of 
commerce. 

Preparation  of  Tannic   Acid.     Pelouze's  Process 

By  this  process,  tannic  acid  is  obtained  by  means  of  a  per- 
colator, a  (Fig.  2)  fitted  into  a  receiver  b.  The  percolator 
is  a  cylindrical  glass  vessel,  open  at  both  ends,  the  upper 
opening  being  fitted  with  an  air-tight  stopper,  and  the 


44 


LEATHER  MANUFACTURE. 


a 


lower  end  adjusted  to  the  neck  of  the  glass  receiver  b. 
The  upper  vessel,  or  percolator,  is  about  half  filled  with 
coarsely-powdered  galls,  which  are  prevented  from  falling 
through  the  lower  opening  by  a  plug  of 
cotton,  and  the  powder  is  then  covered,  in 
successive  portions,  with  ether,  which  has 
been  previously  shaken  up  with  a  little 
water.*  The  stopper  is  now  inserted  in 
the  mouth  of  the  percolator,  and  the  mix- 
ture allowed  to  digest  for  several  hours, 
after  which  the  stopper  is  withdrawn, 
and  the  liquid  allowed  to  filter  into  the 
receiver  beneath.  When  all  the  liquid 
has  passed  through,  the  powdered  galls 
are  washed  with  more  ether  introduced  at 
the  top  as  before.  After  standing  for  a 
short  time,  the  filtered  liquor  will  be  found 
to  separate  into  two  distinct  strata,  of 
unequal  density.  The  tannic  acid  and 
gallic  acid,  being  both  extracted  by  the 
mixture  of  ether  and  water,  now  sepa- 
rate ;  the  lower  stratum  being  a  solu- 
tion  of  tannin  (generally  of  an  amber 
colour)  in  water,  and  the  upper  stratum  an 
etherial  solution  of  other  substances  con- 
tained in  the  galls,  the  most  important 
of  which  is  Gallic  acid.  The  two  solutions  are  next  sepa- 
rated; the  aqueous  solution  of  tannin  is  gently  evapo- 
rated to  dryness  and  finally  exposed  to  an  oven  heat, 
at  a  temperature  not  exceeding  212°  Fahr.  The  result  is 
an  amorphous,  or  uncrystallised  mass  of  tannin,  nearly  if 
not  quite  pure,  the  yield  being  frequently  about  40  to  45 
per  cent,  of  the  weight  of  galls  used.  The  ether  in  the 
lighter  liquid  is  recovered  by  distillation,  over  a  water 
bath,  with  the  aid  of  a  Liebig's  condenser,  supplied  with 
ice-cold  water. 

Berzelius'  Process. — A  hot  infusion  of  galls  is   first 

*  It  is  absolutely  necessary  that  the  ether  should  be  agitated  with 
,  otherwise  not  a  fraction  of  tannin  will  be  obtained. 


Fig.  2. 


TANNIN  OR    TANNIC  ACID.  45 

obtained,  and  to  this  is  added  a  few  drops  of  sulphuric  acid. 
The  mixture  is  to  be  well  agitated,  then  filtered,  and  to 
the  filtered  liquid  sulphuric  acid,  diluted  with  its  own 
weight  of  water,  is  added  gradually,  until  the  precipitate 
formed,  after  standing  for  an  hour,  is  found  in  the  form  of  a 
semi-fluid  gelatinous  mass.  The  liquid  is  then  decanted 
and  carefully  mixed  with  concentrated  sulphuric  acid  so 
long  as  a  precipitate  forms.  The  precipitate  is  then 
washed  with  water  strongly  acidulated  with  sulphuric  acid, 
and  is  then  pressed  between  the  folds  of  bibulous  (filtering) 
paper.  The  precipitate  is  next  dissolved  in  pure  water, 
and  to  the  solution  carbonate  of  lead,  in  very  fine  powder,  is 
added,  and  after  agitation  and  maceration  for  some  time, 
until  the  sulpho-tannate  is  all  decomposed,  the  mixture  is 
again  filtered,  and  the  liquid  gently  evaporated  to  dry  ness. 
The  residuum  is  finally  powdered  and  digested  in  ether, 
which  is  now  allowed  to  evaporate  spontaneously,  and  the 
resulting  powder  is  at  once  bottled  to  preserve  it  from 
the  air. 

Bouillon-Legrange's  Process. — By  this  method,  an  in- 
fusion of  nut-galls  is  precipitated  by  carbonate  of  am- 
monia. The  precipitate  is  afterwards  washed  with  cold 
water,  and  then  digested  repeatedly  in  fresh  quantities  of 
alcohol  at  0*817.  This  process,  however,  does  not  yield 
pure  tannin. 

Merat-Gnillot's  Process. — An  infusion  of  nut-galls  is 
precipitated  by  lime  water,  and  the  precipitate  treated  with 
dilute  nitric  or  hydrochloric  acid.  Effervescence  occurs, 
and  the  liquor  assumes  a  dark  brown  colour.  After  filtra- 
tion, a  bright  black  substance  separates,  which  the  inventor 
assumes  to  be  pure  tannin,  but  according  to  Sir  H.  Davy 
it  is  combined  with  vegetable  extractive  and  a  certain 
portion  of  lime. 

Eize^s  Process. — This  process  consists  in  pouring  con- 
centrated sulphuric  or  hydrochloric  acid  into  a  concen- 
trated infusion  of  nut-galls,  when  a  white  precipitate  is 
produced,  which  Proust  believes  to  be  a  combination  of 
tannin  with  the  acid  employed.  It  is  purified  by  washing 
with  cold  water,  then  dissolved  in  warm  water,  and  the 


46  LEATHER  MANUFACTURE. 

acid  is  saturated  with  carbonate  of  potash.  This  process 
does  not  produce  pure  tannin,  but  a  substance  in  which 
both  gallic  acid  and  extractive  are  present. 

Deyeux's  Process. — By  this  method,  a  strong  infusion 
of  galls  is  precipitated  with  a  concentrated  solution  of 
carbonate  of  potash,  when  an  abundant  yellowish-white 
precipitate  is  formed,  which  on  drying  yields  a  whitish 

S)wder.  The  product,  however,  is  not  pure,  as  proved  by 
avy  and  Tromsdorff ,  who  found  it  to  be  a  combination  of 
tannin,  gallic  acid,  carbonate  of  potash,  and  lime. 

Proust's  Process. — To  an  infusion  of  nut-galls  is 
added  a  solution  of  chloride  of  tin  until  the  precipitate  of 
tannate  of  tin  ceases  to  fall.  A  yellowish-white  precipitate 
is  formed,  which  is  afterwards  washed  and  mixed  with 
cold  water.  A  current  of  sulphuretted  hydrogen  gas  is 
then  passed  through  the  product,  which  is  next  filtered 
and  then  evaporated  to  dryness.  Although  a  tolerably 
pure  product  is  obtained,  the  presence  of  gallic  and 
hydrochloric  acids  and  extractive  in  small  quantities  have 
been  traced. 

Serturner's  Process. — By  this  process  an  alcoholic 
infusion  of  nut-galls  is  precipitated  by  warm  carbonate  of 
potash.  After  decanting  the  liquid,  the  residue  is  washed 
with  alcohol,  and  then  treated  with  sulphuric  acid.  This 
is  then  evaporated,  and  the  residue  treated  with  alcohol. 
The  excess  of  sulphuric  acid  is  precipitated  by  carbonate 
of  lime.  After  filtering,  the  filtrate  is  evaporated  to 
dryness,  when  tannin  containing  very  little  gallic  acid  is 
the  result. 

Schering's  Process. — This  is  called,  by  the  patentee, 
the  "manufacture  of  improved  tannic  acid."  The  thick 
extract,  or  solution  of  tannin,  whether  it  be  combined 
with  water,  alcohol,  or  ether  (!)  is  placed  in  a  heated 
chamber,  the  heat  being  maintained  and  regulated  at  a  low 
temperature,  and  the  air  excluded  as  far  as  possible.  The 
extract  or  solution  is  thus  slowly  evaporated,  until  it  is 
reduced  to  a  thick  pasty  condition.  It  is  then  forced  by 
a  pressing  apparatus  through  a  plate  perforated  with  small 
holes,  from  which  it  exudes  in  thin  filaments,  like  thin 


TANNIN  OR   TANNIC  ACID.  47 

vermicelli  threads ;  these  are  wound,  as  they  exude,  on 
suitable  reels,  or  cylinders,  or  they  may  be  collected  in  any 
convenient  manner.  The  threads  so  obtained,  on  cooling, 
are  very  brittle,  and  will  break  up  into  golden,  shining, 
needle-like  fragments,  which  can  be  readily  collected,  and 
preserved  in  bottles. 

Badvil  and  Lienders'  Process. — The  object  of  this 
invention  is  to  obtain  "  tanning  material  from  the  asphodel 
plant,"  and  is  based  upon  the  discovery  that  this  plant 
contains  tannin  which  does  not  dissolve  under  the  influence 
of  acids  and  fermentation,  and  which  is  not  assimilable, 
being  diffused  or  mixed  with  a  large  proportion  of  water, 
saccharine  matter,  and  other  substances.  To  render  the 
tannin  "  adaptable  for  leather  dressing  like  the  best 
sumacs,  it  is  necessary  to  eliminate  the  main  portion  of 
the  water  and  saccharine  matter."  For  this  purpose  the 
asphodel  is  washed,  to  free  it  from  the  earth  which  may 
adhere  to  it ;  it  is  then  grated  or  crushed  to  break  up  the 
cells,  and  the  pulp  thus  obtained  is  then  pressed.  The 
juice  which  flows  from  it  is  subjected  to  a  complete  fer- 
mentation, to  extract  its  alcohol.  The  pressed  pulp,  which 
contains  nearly  all  the  tannin,  is  dried,  preferably  by 
exposure  to  the  sun,  and  finally  reduced  to  a  powder  or 
extract.  "  It  can  be  used  in  this  state  for  leather-dressing 
purposes." 

MM.  Coe'z's  Process. — The  tanning  matter  or  juices 
being  extracted  by  the  usual  processes,  the  decoctions  are 
placed  in  wooden  vessels,  in  which  they  are  intimately 
subjected  to  the  process  of  decoloration  in  the  following 
manner : — Oxalic  acid  is  first  added  in  the  proportion  of 
one  grain  of  acid  to  every  100  litres*  of  juice,  the  density 
of  which  is  unimportant,  for  the  purpose  of  saturating  the 
lime  which  is  contained  in  the  water  used  in  the  process  of 
extraction,  in  proportions  varying  according  to  the  quality 
of  the  said  water.  After  allowing  a  few  minutes  for  the 
oxalic  acid  to  act,  gelatinous  alumina  is  introduced  in  the 
proportion  of  about  250  grains  per  100  litres  of  juice,  and 

*  1  litre  is  equal  to  34  fluid  ounces  nearly,  or  about  six  ounces  less  than 
.in  Imperial  quart. 


48  LEATHER   MANUFACTURE. 

per  degree  of  the  density.  The  materials  are  now  vigorously 
agitated,  and  the  mixture  being  immediately  filtered,  the 
alumina  remains  upon  the  filter  with  the  colouring  matter. 
The  clear  tannic  liquid,  from  which  the  colouring  matter 
has  thus  been  removed,  is  collected  and  evaporated  in  vacuo 
by  known  means,  and  brought  to  a  density  of  about  20° 
Baume.  The  tannic  extract  obtained  by  this  process  is  said 
to  be  remarkably  pure,  is  soluble,  and  readily  assimilable 
by  hides  or  skins. 

Kohlrausch's  Process. — This  process,  which  is  also 
applicable  to  the  extraction  of  colouring  matters  from  dye- 
woods,  consists  in  first  reducing  the  wood  or  bark  by  cleav- 
ing, breaking,  sawing,  &c.,  to  small  pieces  about  J  inch  to 
3  inches  long,  about  the  same  width,  and  from  ^o  to  J  inch 
thick.  These  pieces  are  placed  in  closed  vessels  of 
copper  or  enamelled  iron,  and  treated  with  water  at  about 
20  to  75  C.  (68°  to  167°  F.),  under  pressure,  so  as  to  ex- 
tract tannic  acid,  &c.,  the  different  vessels  forming  a 
"continuous  working  battery,"  and  being  connected  with 
each  other  by  pipes,  which  may  be  heated  if  desired.  If, 
for  instance,  the  "  battery"  consists  of  twelve  vessels,  pure 
water,  under  pressure,  is  allowed  to  enter  the  first  vessel, 
where  the  process  begins,  and  is  continued  until  the  den- 
sities of  the  liquids  inside  and  outside  the  bark-cells  are 
equalised.  The  liquid  is  afterwards  allowed  to  pass  from 
the  first  into  the  second  vessel,  where  the  tannic  acid 
solution  will  become  more  concentrated.  From  the  second 
vessel  the  liquid  passes  into  the  third,  and  so  on  up  to  the 
eleventh  vessel,  where  the  concentration  of  the  liquid  is 
almost  equal  to  that  in  the  cells  containing  the  raw 
materials.  During  that  time,  pure  water  has  been  supplied 
to  the  first  vessel,  by  which  its  contents  become  exhausted 
and  may  be  discharged.  Pure  water  is  now  admitted  to 
the  second  vessel,  and  the  twelfth  filled  with  raw  material. 
The  extracted  liquid  is  afterwards  made  to  pass  into  the 
twelfth  vessel,  the  first  filled  with  raw  material,  the  second 
discharged,  and  pure  water  allowed  to  flow  into  the  third 
vessel,  and  so  on,  in  such  a  manner  that  the  contents  of  ten 


TANNIN  OR    TANNIC  ACID.  49 

vessels  are  continuously  subjected  to  dialysis*  The 
necessary  temperature  of  the  water  may  be  maintained  by 
providing  the  connecting  pipes  with  heaters  of  any  suitable 
construction.  The  extract  obtained  by  this  process  may  be 
further  concentrated  in  vacuum  pans,  or  may  be  employed 
directly  for  the  manufacture  of  leather. 

Properties  of  Tannic  Acid.— This  acid,  as  it  exists  in 
different  vegetables,  varies  in  its  chemical  reactions,  some- 
times in  a  very  marked  degree.  According  to  Gmelin, 
the  following  plants  contain  the  modification  of  tannin 
which  renders  solutions  of  peroxide  of  iron  (as  the  persul- 
phate of  iron  for  example)  a  deep  Hue  : — Galls,  the  roots  of 
Lithnun  salicaria,  Geum  urbanum,  and  rivalc,  Potcntilla 
argentea  and  anserina,  Arctium  lappa,  Sanguisorba  officinalis, 
Poterium  sanguisorba,  Alchcmilla  vulgaris,  Polygonum  bistorta, 
Iris  2)sciidacorus,  Nymphcea  alba,  the  wood  of  the  oak,  and 
many  other  trees,  the  bark  of  different  species  of  oak,  the 
leaves  of  oak,  Uva  ursi,  and  many  others,  the  twigs  of  the 
black  currant  and  sumac,  the  petals  of  pomegranate,  Rosa 
gallica  and  Pwonia  officinalis.  The  tannin  which  gives  a 
green  precipitate  with  persalts  of  iron  is  found  in  Catechu 
and  Kino,  in  the  roots  of  the  Tormentilla  ereda,  Potentilla 
reptans,  Rosa  canina,  Rheum  rhaponticum,  &c.,  in  the  diffe- 
rent species  of  Cinchona  bark,  in  Cinnamon,  Cassia,  and  in 
horse-chestnut  bark;  in  the  leaves  of  Salcia  officinal^, 
Lamium  album,  Glccoma  hcderacea,  &c.,  in  the  varieties  of 
tea;  in  tho  flowers  of  Tilia Europcea,  Centauria  cyanus,  and 
Arnica  montana;  in  horse-chestnuts,  date-stones,  &c. 

*  In  practical  chemistry,  the  method  of  separating  substances  by  "  diffu- 
sion," through  a  hoop  covered  with  paichment  paper,  is  called  dialysis. 
When  a  solution  having  a  higher  specific  gravity  is  introduced  into  a 
cylindrical  glass  vessel,  and  water  then  very  cautiously  poured  into  it  in 
such  a  way  that  the  two  layers  of  liquid  remain  unmoved,  the  substance 
dissolved  in  the  lower  liquid  will  gradually  pass  into  the  supernatant 
water,  though  the  vessel  may  have  been  left  undisturbed,  and  the  tempera- 
ture remain  unchanged.  The  gradual  passage  of  a  dissolved  substance 
Irom  its  original  solution  into  pure  water  takes  place  notwithstanding  the 
higher  specific  gravity  of  the  substance  which  opposes  this  passage  ;  this 
is  called  "  diffusion  of  liquids,"  the  investigation  of  which  was  due  to 
the  late  Professor  Graham,  of  the  Royal  M  int. 

K 


SO  LEATHER  MANUFACTURE. 

According  to  the  experiments  of  Berzelius  and  others, 
the  tannin  in  all  plants  is  essentially  the  same  substance, 
the  different  colours  of  the  various  precipitates  with  per- 
salts  of  iron  depending  on  the  accidental  presence  of 
impurities,  and  also  on  the  nature  of  the  salt  of  iron  used. 
But  the  more  recent  researches  of  Dr.  Stenhouse  favour 
the  conclusion  that  not  only  must  the  tannins  of  different 
plants  which  produce  different  coloured  precipitates  in 
the  same  solution  of  peroxide  of  iron  be  regarded  as 
distinct  substances,  but  even  that  some  of  the  varieties 
of  tannin  which  agree  in  their  reaction  upon  salts  of 
iron,  and  in  their  general  chemical  habitudes,  are  by 
no  means  identical.*  Dr.  Stenhouse  availed  himself  of 
a  new  test  for  tannin,  which  affords  indications  only  with 
the  variety  of  tannin  contained  in  galls,  and  with  gallic 
acid,  which  consists  in  the  production  of  pyrogallic  acid, 
when  the  body  to  be  tested  is  subjected  to  destructive 
distillation :  pyrogallic  acid  is  disengaged  as  a  crystalline 
sublimate. 

Farneirs  Views. — This  chemist  observes :  "  Although 
the  astringent  matter  contained  in  several  vegetables  is 
designated  by  the  same  name,  tannin,  or  tannic  acid,  yet 
all  these  bodies  do  not  appear  to  be  identical.  The  differ- 
ences, however,  which  are  perceptible  in  the  properties  of 
most  of  the  substances  which  are  thus  classed  together 
are  small,  and  seemingly  of  no  great  importance  in  the 
practical  application  of  this  vegetable  principle.  Other 
vegetable  matters  exist,  the  properties  of  which  amply 
distinguish  them  from  tannin.  The  most  characteristic 
properties  of  tannin  are,  astringency  in  taste,  and  the 
power  of  being  precipitated  from  its  aqueous  solution, 
either  of  a  bluish-black,  or  dark  green  colour,  by  a 
solution  of  the  peroxide  of  iron,  and  of  a  dirty  white,  or 

*  It  is  now  generally  recognised  that  although  the  numerous  varieties 
of  tannin  all  possess  the  common  property  of  precipitating  gelatine,  not 
only  do  they  differ  greatly  in  their  chemical  reactions,  but  the  leather 
produced  from  them  is  of  very  varied  character — sometimes  of  very  indiffe- 
rent quality ;  and  were  it  not  for  the  custom  of  mixing  certain  tanning 
materials  with  others  of  known  excellence,  it  is  doubtful  whether  some  of 
them  would  not  be  altogether  abandoned. 


TANNIN  OR    TAN  NIC  ACID.  51 

brown  colour,  by  a  solution  of  gelatine.  The  precipitate 
produced  in  a  solution  of  a  persalt  of  iron,  which  is  the 
tannate  of  peroxide  of  iron,  is  the  basis  of  common  writing 
ink.  A  solution  of  protosulphate  of  iron  (copperas),  per- 
fectly free  from  all  peroxide  of  iron,  experiences  no 
immediate  change  on  the  addition  of  tannin ;  but  the 
mixture  instantly  becomes  deep  blue  or  black  on  exposure 
to  the  air,  through  the  absorption  of  oxygen,  and  forma- 
tion of  peroxide  of  iron.  If  cold  aqueous  solutions  of 
tannin  and  animal  gelatine  (glue,  bone-size  or  isinglass), 
are  mixed  in  certain  proportions,  both  of  these  bodies  are 
ulmost  completely  thrown  down  as  a  precipitate,  known  by 
the  name  of  tanno-gclatinc,  which  generally  contains  about 
half  its  weight  of  tannin.  Sometimes,  particularly  when 
heat  is  applied,  or  when  the  acid  is  in  excess,  the  pre- 
cipitate forms,  on  stirring,  a  very  viscid  and  elastic  mass, 
somewhat  resembling  caoutchouc.  In  its  chemical  condi- 
tion, tanno- gelatine  is  quite  analogous  to  leather,  and  was 
at  one  time,  in  fact,  generally  regarded  as  that  substance 
in  a  pure  state.  This  cannot  be  the  case,  however,  as 
gelatine  does  not  exist  ready  formed  in  the  skin  (according 
to  Berzelius)  and  tanno-gelatine,  unlike  leather,  is  slightly 
soluble  in  water  at  the  boiling  point.  The  aqueous 
solution  becomes  turbid  on  cooling,  owing  to  the  re-pre- 
cipitation of  the  tanno-gclatine.  This  compound  may 
also  be  dissolved  by  an  excess  of  a  solution  of  gelatine, 
but  not  by  an  excess  of  a  cold  solution  of  tannin.  When 
dried,  it  loses  its  viscidity  and  elasticity,  and  becomes 
brittle  and  pulverulent." 

Pure  Taxmic  Acid  is  nearly  colourless,  inodorous,  pre- 
eminently astringent  in  taste,  uncrystallisable,  very  soluble 
ill  water,  and  less  soluble  in  pure  alcohol  and  ether.  Its 
aqueous  solution  reddens  litmus,  and  decomposes  the 
alkaline  carbonates,  with  effervescence.  It  combines 
energetically  with  gelatine ;  when,  therefore,  a  piece  of 
skin  or  bladder  is  immersed  in  its  aqueous  solution,  the 
tannic  acid  is  entirely  abstracted ;  whereas,  if  gallic  acid 
were  present,  that  acid  remains  dissolved  in  the  water. 
Tannic  acid  also  furnishes  an  abundant  white  precipitate 


52  LEATHER   MANUFACTURE. 

in  solutions  of  isinglass  or  glue.  A  concentrated  aqueous 
solution  of  tannic  acid  is  precipitated  by  hydrochloric, 
nitric,  sulphuric,  phosphoric,  and  arsenic  acid ;  but  not 
by  oxalic,  tartaric,  lactic,  acetic  or  citric  acid.  By  the 
prolonged  action  of  acids  and  alkalies,  tannic  acid  under- 
goes various,  and  often  complicated,  changes,  amongst 
which  its  conversion  into  gallic  acid  is  the  most  common. 
— Brande. 

By  exposure  to  the  air,  a  solution  of  tannic  acid 
gradually  becomes  turbid,  and  deposits  a  grey  crystalline 
powder,  which  is  gallie  acid.  By  contact  with  the  air 
oxygen  is  absorbed,  and  an  equal  volume  of  carbonic  acid 
is  evolved  ;  only  a  portion  of  the  tannic  acid,  however,  is 
thus  decomposed,  and  is  converted  into  gallic  and  ellagic 
acids.  It  is  the  opinion  of  many,  that  the  gallic  acid 
present  in  gall  nuts  is  due  to  the  absorption  of  oxygen 
by  the  tannic  acid,  during  the  process  of  vegetation. 
And  to  this  end,  possibly,  the  insect  which  inhabits  the 
gall  nut  during  its  development,  may  be  the  real  active 
agent. 

Reactions  of  Tannic  Acid. — The  following  reactions 
of  tannic  acid  are  given  by  Abel  and  Bloxam*  : — 

Concentrated  sulphuric  acid,  treated  with  (solid)  tannic 
acid,  produces,  immediately,  a  dark,  purplish-black  liquid, 
but  does  not  evolve  carbonic  oxide. 

When  heated  on  platinum,  tannic  acid  burns,  chars,  and 
emits  a  peculiar  odour. 

Alkalies,  added  to  a  solution  of  tannic  acid,  cause  it  to 
absorb  oxygen  from  the  air,  and  to  assume  a  brown  colour. 

Sesquichloride  of  iron  produces  a  bluish-black  precipi- 
tate of  tannate  of  sesquioxide  of  iron. 

Dilute  sulphuric  (or  hydrochloric)  acid  produces,  in  a 
pretty  concentrated  solution  of  tannic  acid,  a  white  pre- 
cipitate, which  is  an  insoluble  compound  of  the  two 
acids. 

Tannin  is  precipitated  from  a  tolerably  strong  solution 
of  the  mineral  acids,  and  these  precipitates  consist,  according 

*  «*  Handbook  of  Chemistry."     By  F.  A.  Abel  and  C.  L.  Bloxain. 


TANNIN  OR    TANNIC  ACID. 


S3 


to  Berzelius,  of  compounds  of  tannin  with  the  acids  respec- 
tively. If  the  compound  with  sulphuric  acid  be  boiled  for  a 
few  minutes  in  dilute  sulphuric  acid,  the  tannin  becomes  con- 
verted into  gallic  acid,  which  is  deposited  in  coloured 
crystals  on  cooling.  When  the  sulphuric  acid  employed 
for  this  purpose  is  diluted  with  7  or  8  times  its  bulk  of 
water,  the  crystals  of  gallic  acid  are  colourless  and  nearly 
pure.  A  similar  change  occurs  according  to  Liebig  where 
the  compound  of  tannin  and  sulphuric  acid  is  boiled  with 
an  excess  of  caustic  alkali ;  and  the  action  of  hydrochloric 
acid  on  tannin  is  quite  the  same  as  that  of  sulphuric  acid.— 
(Stenhousc.}  In  these  cases  of  the  conversion  of  tannin  into 
gallic  acid,  the  action  of  the  air  is  unnecessary. 


TABLE  OF  THE  PEUCENTAOB  OF  TANNIN  IN  VEGETAHLE  SUHSTANCKS. 


Substance. 


Per  Centage 

of  T.  inn  in. 


Catechu,  Bombay   55'0 

„  „        light  colour 26%3 

„        Bengal 44'0 

„        Peru,  dark  brown  colour  . .  46'8 

Rhatanyroot    42-6 

„.    38-3 

Kino — Tannin  and  Extractive 75'0 

Butea  Gum 73*2 

Nut  Galls,  Aleppo 70-0 

Chinese 74-0 

,,          Istrian   24-0 

Old  Oak,  white  inner  bark    21-0 

14-2 

Young  Oak,  white  inner  bark 15 '2 

„  coloured,  or  middle  bark       4'0 

„  entire  baik     6'0 

,,  spring-cut  bark     22 -0 

Oak,  Kermes,  bark  of  the  root 8'9 

„     100  years  old   8'5 

„    young    13-8 

„    British  50  years  old    8-9 

„    Coppice 12-5 

„    Irish  45  years  old    9-50 

„    Belgian '. . .       8-3 

Terra  Japonica,  or  Gambier 44'0 

Avens  root,  Gewn  urbanum    41-0 

Squill,  bulb 24'0 

Statice  of  South  Carolina 12-4 


Authority. 

Davy. 
Mulligan. 


Peschier. 
Gmolin. 
Vauquelin. 
E.  Solly. 
Crookes. 

i> 

Rhodes. 

Cadet  de  Gassincourt. 
Davy. 


Davy  and  Geiger. 

Davy. 

Davy  and  Geiger. 

Muller. 

»» 
Mulligan  and  Downing. 


Eisenbeck. 
Tromsdorff. 
Vogel. 
Parrish. 


54 


LEATHER  MANUFACTURE. 


Substance. 

Birch  bark    1-6  ..  Davy. 

»           1-4  ..  Biggers. 

Beech  bark  2-0  . .  Davy. 

Larch  bark   1-6  . .  „ 

Hazel  bark    3-0  ..  ,, 

Chestnut,  American  rose  8-0  . .  Cadet  de  Gassincourt. 

Carolina 6-0  . .  ,, 

French    4-0  ..  De  Fontenelle. 

Spanish,  white  inner  bark  1-3  ..  Davy. 
,,       coloured  or  middle 

bark 0-3  ..  ,, 

,,        entire  bark 0-5  ..  ,, 

horse    2-0  . .  De  Fontenelle. 

Lombardy  Poplar 3- 5  . .  ,, 

Blackthorn  3-3  . .  Davy. 

Ash  bark 3-3  ..  „ 

Sassafras,  burk  of  the  root    58-0  . .  Reinsch. 

Elm  bark 2-9  . .  Davy 

Sumac,  Sicily 24-0  . .  Crookes. 

Malaga     16-4  ..  Davy. 

,,      10-4  ..  Franck. 

Carolina 5'0  . .  Cadet  de  Gassincourt. 

Virginia 27'0  . .  Anon. 

„     19-5  ..  Muller. 

Willow,  Leicester,  white  inner  bark  IG'O  ..  Davy. 
,,               ,,         coloured  or  middle 

bark 3-0  ..  „ 

„              ,,         entire  bark 6'8  . .  ,, 

,,              ,,             ,,         „    3*9  ..  Mulligan  and  Downing. 

,,               „         bark  of  the  trunk  T4  ..  Biggers. 

,,        weeping    16*0  ..  Cadet  de  Gassiucourt. 

Sycamore  bark    1G-0  . .  „ 

,,           ,,        1-4  ..  Biggers. 

Elder     2-3  . .  Davy. 

Plum  tree 1  '6  . .  Biggers. 

Cherry  tree 24-0  . .  Cadet  de  Gassincourt. 

,,        ,,     Cornish   19-0  ..  ,, 

Tormentilroot 46gO  ..  ,, 

Cornus  sanguinea  of  Canada 44-0  . .  ,, 

Alder  bark   36'0  ..  „ 

Hemlock 13'9  . .  Mulligan  and  Downing. 

Divi  divi 50-0  . .  Crookes. 

,,        49-2  ..  Muller. 

Valonia    34-7  ..  Mulligan  and  Downing. 

Myrobalans     35-0  ..  Crookes. 

Mimosa  bark     17'8  ..  Mulligan  and  Downing. 

„        „       31-1  ..  Muller. 

Apricot  bark    32'0  ..  De  Gassincourt. 

Pomegranate   32*0  ..  „ 

Bohemian  olive 14-0  ..  „ 


TANNIN  OR    TANNIC  ACID.  55 


Substance.  rf  Authority. 

Tan  shrub,  with  myrtle  leaves  ......  13'0  .  .  De  Gassincourt. 

Service  tree,  bare,  June  berry  ......  18-0  .  .  ,, 

Cloves  ..........................  lo-O  ..  Davy. 

Winter's  bark  ...................  9-0  .  .  Henry. 

The  more  recent  methods  of  estimating  tannin  which 
have  been  introduced  since  the  foregoing  determinations 
were  arrived  at,  render  it  advisable  that  the  percentage 
in  this  Table  should  be  received  with  caution  ;  at  the 
same  time  it  must  be  admitted  (owing  to  the  difference 
which  exists  between  tannins  obtained  from  different 
sources),  that  even  the  more  modern  determinations  of 
this  substance  are  not  wholly  reliable. 

Morfit's  Observations.—  1.  That  tannin  is  never  found 
to  any  extent  in  the  interior  of  the  trunk  of  trees.  "2.  That 
it  does  not  exist  in  poisonous  plants,  nor  in  those  with  a 
milky  or  viscid  sap.  3.  That  its  proportion  is  greater  in 
young  than  in  old  plants.  4.  That  the  tannin  is  converted 
into  bitter  principle,  as  the  plant  increases  in  age.  5.  That 
it  is  most  abundant  in  the  cortical  layers  of  the  bark,  and 
is  usually  absent  altogether  in  the  epidermis.  6.  That  the 
proportion  of  tannin  in  bark  varies  with  the  season,  de- 
creasing as  the  severity  of  the  winter  increases,  and  7. 
That  the  two  extremes  of  the  quantity  are  attained  in  winter 
and  spring. 

Artificial  Tannin.  —  According  to  Hatchett,*  a  substance 
having  some  of  the  characteristics  of  tannin,  and  to  which 
the  name  artificial  tannin  has  been  given,  may  be  formed 
by  digesting  charcoal  in  dilute  nitric  acid  for  several  days. 
The  charcoal  is  at  length  dissolved,  and  a  reddish-brown 
liquor  is  obtained,  which  yields,  after  careful  evaporation, 
a  brown  glossy  substance,  amounting  to  about  120  parts, 
from  100  parts  of  charcoal.  This  artifical  tannin  differs 
in  one  particular  from  natural  tannin,  namely,  that  it  resists 
the  action  of  nitric  acid,  which  decomposes  all  varieties  of 
natural  tannin,  though  some  are  more  capable  of  resisting 
its  action  than  others.  Artificial  tannin  has  a  somewhat 

*  Philosophical  Transactions,  1805-6. 


56  LEATHER  MANUFACTURE. 

bitter,  astringent  taste,  is  soluble  in  water,  and  forms  an 
insoluble  precipitate  in  solutions  of  animal  gelatine,  con- 
sisting, according  to  Hatchett,  of 

Artificial  tannin 36 

Gelatine 64 

100 

Hydrochloric  and  sulphuric  acids  produce  brown  precipi- 
tates in  solutions  of  artificial  tannin,  which  are  soluble  in 
hot  water.  A  variety  of  artificial  tannin  may  be  formed  by 
digesting  camphor  and  resins  in  sulphuric  acid,  until  the 
liquor  becomes  black,  and  on  being  poured  into  water 
deposits  a  black  powder,  which  being  digested  in  alcohol 
yields  a  brown  matter,  soluble  in  water,  and  which  pro- 
duces an  insoluble  precipitate  with  gelatine. 


CHAPTER  V. 
GALLIC  ACID. 

Gallic  Acid.— Preparation  of  Gallic  Acid  from  Galls.— Scheele's  Mothod.- 
Liebig's  Method.— Graham's  Method.— Pharmaceutical  Method*.— 
Properties  of  Gallic  Acid. — Pyrogallic  Acid. — Ellagic  Acid. 

Gallic  Acid. — The  frequency — nay  almost  constancy— 
with  which  gallic  acid  is  associated  with  the  great  astrin- 
gent tanning  principle,— tannic  acid, — and  the  ready  con- 
version of  the  latter  into  the  former,  by  the  influence  of 
oxygen,  renders  it  advisable  that  it  should  be  considered 
apart  from  its  associates,  more  especially  since  this  vege- 
table acid  often  plays  an  important  though  an  objection- 
able part  in  the  process  of  tanning.  Gallic  acid  was 
discovered  by  Scheele,  and  various  methods  of  obtaining  it 
in  a  pure  state  were  afterwards  devised  by  Deyeux, 
Braconnot,  Liebig,  and  Dr.  Stenhouse.  The  conversion  of 
tannic  acid  into  gallic  acid  by  the  agency  of  oxygen  was 
first  demonstrated  by  Pelouze ;  and  the  existence  of  the 
latter  acid,  independent  of  tannic  acid,  in  several  vegetables, 
has  been  proved  both  by  Dr.  Stenhouse  and  Robiquet. 
Since  this  acid,  however,  is  almost  always  associated  with 
tannic  acid  in  the  various  plants  which  yield  these 
substances,  and  moreover  exists  in  much  smaller  propor- 
tions than  the  tanning  principle — often  a  mere  trace — it 
may  not  be  unreasonable  to  infer  that  the  existence  of 
gallic  acid  is  due  to  the  oxidation  of  the  tannic  acid 
generated  or  secreted  by  plants,  and  that  it  is  not  formed 
in  nature  as  a  separate  and  distinct  substance.  This  view 
is  supported  by  the  readiness  with  which  tannic  acid  com- 
bines with  oxygen,  when  exposed  to  the  air  under  certain 


5»  LEATHER  MANUFACTURE. 

conditions,  as  we  find  when  considering  its  mode  of  prepa- 
ration from  gall  nuts. 

Preparation  of  Gallic  Acid  from  Galls. — The  process 
recommended  by  Dumas  is  as  follows  :  A  quantity  of  nut- 
galls  are  reduced  to  powder,  and  this  is  next  made  into  a 
paste  with  water  ;  in  this  state,  the  mass  is  exposed  to  the 
action  of  the  air,  in  a  warm  situation,  the  temperature 
being  from  70°  to  80°  Fahr.,  for  two  or  three  months,  more 
water  being  added  from  time  to  time,  to  make  up  for  that 
which  is  lost  by  evaporation.  At  the  end  of  the  above 
period,  the  mouldy,  dark- coloured  mass  is  strongly  pressed 
in  a  cloth,  and  the  solid  portion  boiled  in  a  considerable 
quantity  of -water.*  The  solution  is  to  be  filtered  whilst 
hot,  and  on  cooling,  crystals  of  gallic  acid  will  deposit  at 
the  bottom  of  the  vessel.  These  crystals  are  afterwards 
to  be  well  drained,  and  pressed  between  folds  of  white 
blotting  paper,  and  they  are  next  to  be  purified,  by  boil- 
ing them  with  about  one- sixth  of  their  weight  of  pre- 
pared animal  charcoal  in  eight  parts  of  water.  The  solu- 
tion is  to  be  again  filtered  whilst  hot,  and  the  clear  liquor 
set  aside  to  cool,  when  pure  crystals  of  gallic  acid  will 
be  obtained,  which  must  be  well  drained  and  dried  over  a 
water-bath. 

Scheele's  Method. — A  filtered  decoction  of  galls  is 
exposed  to  the  air  for  some  months,  in  an  open  vessel ; 
after  a  time  it  grows  mouldy,  and  becomes  covered  with 
a  thick  glutinous  pellicle,  or  scum  ;  in  two  or  three  months 
the  sides  of  the  vessel,  and  under  portion  of  the  pellicle, 
are  found  to  be  covered  with  small  yellow  crystals  of  gallic 
acid,  which  may  be  purified  as  above. 

Liebig's  Method. — To  a  strong  aqueous  solution  of 
tannic  acid,  sulphuric  acid  is  added  so  long  as  a  precipitate 
falls ;  the  powder  is  collected,  washed  and  dissolved  by 
heat,  in  dilute  sulphuric  acid;  the  solution,  after  boiling  for 
a  few  minutes,  and  then  being  allowed  to  cool,  deposits 
abundant  crystals  of  gallic  acid. 

Graham's  Method. — A  strong  infusion  or  decoction  of 

*  Gallic  acid  is  soluble  in  100  parts  of  cold  water,  and  in  3  parts  of 
boiling  water. 


GALLIC  ACID. 


59 


galls  is  precipitated  with  sulphuric  acid  in  the  cold ;  the 
resulting  thick  mass  is  mixed  with  cold  dilute  sulphuric 
acid,  and  the  liquid  pressed  out.  The  "marc"  is  next 
treated  with  sulphuric  acid,  diluted  with  twice  its  weight 
of  water,  and  after  boiling  the  mixture  for  some  minutes, 
the  whole  is  set  aside  to  cool ;  the  resulting  crystals  are 
purified  with  animal  charcoal,  as  before. 

Pharmaceutical  Methods. — The  Dublin  Pharmacopeia 
gives  two  methods  of  preparing  gallic  acid,  one  of  which 
is  based  upon  the  process  of  Dumas,  or  Scheele,  and 
the  other  on  that  of  Graham  or  Liebig.  1.  Galls,  in 
coarse  powder,  1  Ib.  ;  make  into  a  stiff  paste  with  water, 
and  place  in  a  porcelain  dish,  and  expose  in  the  moistened 
condition  for  six  weeks.  The  solution  of  the  first  crop  of 
crystals  is  made  in  10  fluid  ounces  of  boiling  icatcr,  and 
then  filtered.  When  the  filtrate  (the  filtered  liquor)  has 
cooled  down  to  80°  Fahr.,  it  is  to  be  poured  off  from  the 
crystals  which  have  formed,  and  the  crystals  are  to  be 
washed  with  ice-cold  water,  3  fluid  ounces,  and  then  drained 
mid  dried — first  on  blotting  paper,  and  finally  by  steam  or 
water  heat.  By  boiling  the  undissolved  portion  of  the 
galls  with  45  fluid  ounces  of  fresh  water,  more  crystals  are 
obtained.  2.  One  pound  of  powdered  nut-galls  are  steeped 
for  24  hours  in  1  pint  of  water,  and  after  being  placed  in 
a  porcelain  displacement  apparatus,  are  treated  with  one 
and  a  half  pint  of  water,  added  in  successive  portions  ;  5 
fluid  ounces  of  oil  of  vitriol,  diluted  with  an  equal  bulk 
of  water  and  allowed  to  cool,  is  then  added  to  the  perco- 
lated infusion,  and  when  thoroughly  mixed,  the  liquid  is 
filtered  from  the  precipitate  which  forms.  Oil  of  vitriol 
5  fluid  ounces  diluted  with  an  equal  bulk  of  water  as 
before,  is  now  added  to  the  filtrate ;  the  precipitates, 
enveloped  in  calico,  are  submitted  to  powerful  pressure, 
and  subsequently  dissolved  in  a  solution  composed  of  oil 
of  vitriol  16  fluid  ounces,  and  water  56  fluid  ounces.  The 
solution  is  then  boiled  for  20  minutes,  and  set  aside  for  a 
week,  at  the  end  of  which  time  the  deposit  which  forms  is 
dissolved  in  three  times  its  weight  of  boiling  water,  and  the 
solution  treated  as  before. 


60  LEATHER   MANUFACTURE. 

Properties  of  Gallic  Acid. — Pure  gallic  acid  assumes 
the  form  of  white  or  nearly  colourless  feathery  crystals  of 
a  beautiful  silky  lustre ;  the  commercial  acid,  however,  is 
usually  of  a  pale  yellow  colour ;  it  is  soluble  in  alcohol,  and 
also,  sparingly,  in  ether ;  its  solution  in  water  undergoes 
decomposition  when  exposed  to  the  air.  When  strongly 
heated,  gallic  acid  is  converted  into  meta-gallic  acid,  or 
into  pyrogallic  acid,  according  to  the  way  in  which  the 
heat  is  applied.  Gallic  acid  is  distinguished  from  tannic 
acid  by  not  precipitating  gelatine  from  its  solution,*  and 
by  not  affecting  the  proto-s&lts  of  iron  (as  proto-siilphate  of 
iron,  for  example),  and  by  giving  a  deep  bluish-black  pre- 
cipitate with  sesqui  or  per  salts  of  iron  (as  persulphate  of 
iron]  which  disappears  when  the  liquor  is  heated.  It  is 
distinguished  from  pyrogallic  acid  by  its  inferior  solubility 
in  water.  If,  in  a  mixed  solution  of  gallic  acid  and  tannic 
acid,  a  piece  of  depilated  skin  be  immersed  for  some  time, 
the  whole  of  the  tannin  will  be  absorbed  by  the  skin,  leav- 
ing the  unaltered  gallic  acid  in  solution. 

Gallic  acid  is  useless  for  tanning  purposes,  therefore  it  is 
of  considerable  importance  to  prevent,  as  far  as  possible, 
the  conversion  of  the  tannin  contained  in  the  tanning  liquors 
into  gallic  acid — a  change  that  is  more  likely  to  occur 
when  ooze  or  infusion  of  the  astringent  matter  is  used, 
than  when  ground  bark  and  water  only  is  employed,  as  in 
the  old  tanning  process.  When  tanning  solutions  undergo 
decomposition,  a  considerable  percentage  of  tannin  is  con- 
verted into  gallic  acid  and  other  modifications  of  tannic 
acid,  by  which  a  positive  loss  of  tanning  power  is  sus- 
tained. The  tannin  from  galls  and  sumac  is  very  liable 
to  undergo  this  change,  in  consequence,  probably,  of  the 
insoluble  matters  acting  as  a  ferment,  and  thereby  pro- 
moting the  conversion  of  tannin  into  gallic  acid.f  This 
subject  will  be  further  considered  when  treating  of  gallic 
fermentation. 

Although  gallic  acid  possesses  no  tanning  property,  its 

*  Pure  gallic  acid  will  not  throw  down  a  precipitate  from  a  solution  of 
isinglass. 

t  Parnell  thinks  that  the  malio  acid  existing  in  sumac  leaves  is  the 
cause  of  the  rapid  lermontation  of  sumac  liquors. 


GALLIC  ACID.  61 

existence  in  spent  or  exhausted  tan  liquors  is  sometimes 
taken  advantage  of  to  swell  the  hides  after  they  have  been 
limed  in  the  usual  way,  instead  of  employing  dilute 
sulphuric  acid,  by  which  the  absorption  of  the  tannin  is 
promoted. 

Besides  being  present  ready  formed  in  galls  and  sumac, 
gallic  acid  occurs  in  some  other  vegetables ;  it  is  said  to  be 
found  in  the  seeds  of  the  mango-tree,  in  divi  divi,  valonia, 
black  and  green  teas  and  myrabolams. 

Fyrogallic  Acid. — When  gallic  acid  is  subjected  to  dry 
distillation,  at  a  temperature  between  410°  and  420°  Fahr., 
a  white  crystalline  substance  distils  over,  which  is  pyrogallic 
acid.  Its  preparation,  according  to  the  method  suggested 
by  Dr.  Stenhouse,  is  as  follows:— Finely  powdered  galls 
are  treated  with  successive  portions  of  cold  water  till  ex- 
hausted, and  the  infusions  carefully  evaporated  to  dryness, 
when  they  leave  a  spongy,  deliquescent  (that  is,  capable  of 
absorbing  the  moisture  from  the  air;  mass,  which  is  to  be  pul- 
verised and  spread  equally  over  the  bottom  of  a  cast-iron  pan, 
3  or  4  inches  deep,  and  about  a  foot  in  diameter,  the  top  of 
which  is  covered  with  a  diaphragm  of  bibulous  paper  (filter- 
ing paper)  pasted  round  its  rim,  pierced  with  pin  holen,  and 
surmounted  by  a  paper  cap  12  to  18  inches  high.  The  pan 
is  then  cautiously  heated  for  10  or  12  hours,  over  an  oil- 
bath,  so  as  to  preserve  its  temperature  as  nearly  as  possible 
at  about  400°  Fahr.*  The  crystals  of  sublimed  pyrogallic 
acid  collect  in  the  cap,  and  the  other  products  are  chiefly 
absorbed  and  retained  by  the  paper  diaphragm. 

Pyrogallic  acid  is  white,  crystalline,  without  odour,  and 
of  a  bitter  taste.  When  pure  it  does  not  redden  litmus 
paper ;  it  is  very  soluble  in  water,  ether  and  alcohol.  This 
acid  has  been  much  used  in  photography,  its  application 
having  been  first  suggested  by  the  author's  late  friend,  Mr. 
Frederick  Scott  Archer — the  inventor  of  the  well-known 
"  collodion  process." 

*  If  the  heat  of  the  bath  be  rapidly  increased,  and  the  oil  allowed  to 
boil,  carbonic  acid  will  be  given  off,  instead  of  the  crystalline  sublimate, 
water  will  distil  over,  and  a  brilliant  black  mass  left  behind,  which  has 
been  called,  by  Pelouze,  Metagallic  acid,  a  tasteless,  insoluble  substance, 
resembling  carbon,  but  nevertheless  a  true  acid. 


62  LEATHER  MANUFACTURE. 

Ellagic  Acid. — This  name,  which  is  derived  from  the 
word  galle,  read  backwards,  was  given  by  Braconnot  to  a 
substance  formed  along  with  gallic  acid  when  moistened 
galls  are  exposed  for  some  time  to  the  air.  Its  existence 
was  first  noticed  by  Chevreul.  According  to  Grischow, 
ellagic  acid  exists  in  the  root  of  Tormcntilla  crccta.  Being 
insoluble  in  boiling  water,  it  remains  after  the  gallic  acid 
has  been  extracted,  and  may  be  dissolved  out  of  the  residue 
by  a  very  weak  solution  of  potash.  If  dilute  hydrochloric 
acid  be  now  added  to  this  solution,  a  brownish  precipitate 
is  formed,  which  is  ellagic  acid,  a  tasteless  substance  almost 
insoluble  in  water,  alcohol,  and  ether.  It  slightly  reddens 
litmus  paper.  The  bloom  which  appears  upon  the  surface 
of  tanned  skins  or  hides,  is  ellagic  acid. 

Besides  the  above  acids,  there  are  numerous  other  deri- 
vatives of  tannin,  which,  however  interesting  in  themselves, 
are  of  no  importance  to  the  tanner,  and  therefore  need  not 
be  dwelt  upon  in  these  pages. 


CHAPTER  VI. 
GALLIC  FERMENTATION. 

Checking  or  Preventing  Gallic  Fermentation. 

IT  being  an  established  fact  that  tannic  acid,  under  the 
influence  of  moisture  and  atmospheric  air,  becomes  con- 
verted into  gallic  acid,  it  will  readily  be  understood  that 
tan  liquors,  which  are  constantly  exposed  to  the  air,  will 
naturally  be  susceptible  of  this  change,  and,  as  a  conse- 
quence, a  portion  of  their  active  principle  (tannin)  must 
in  course  of  time  suffer  decomposition.  Apart  from  this, 
however,  a  fermentative  process  takes  place  in  the  liquors, 
by  which  a  considerable  proportion  of  the  active  principle 
is  converted  into  gallic  acid ;  this  is  denominated  gallic 
fermentation,  and  has  been  a  constant  source  of  trouble  and 
loss  to  the  tanner.  According  to  the  researches  of  Larocque, 
the  peculiar  ferment  of  nut  galls  which  operates  the 
change,  also  converts  sugar  into  alcohol  and  carbonic  acid, 
in  the  same  way  that  yeast  does,  whilst  beer  yeast,  mus- 
cular flesh,  and  caseous  matter  (the  solid  matter  of  milk) 
change  tannin  into  gallic  acid.  Hence  gallic  and  vinous 
fermentation  are  considered  to  be  nearly  identical. 

According  to  "Wackenroder  and  Larocque,  it  appears 
that  the  formation  of  gallic  acid  from  tannin  is  consider- 
ably expedited  by  the  contact  of  the  insoluble  vegetable 
matters  which  remain  after  the  extraction  of  the  tannin, 
at  least  in  the  case  of  nut-galls,  and  probably  in  that  of 
all  vegetable  matters  containing  tannin  susceptible  of  this 
change  by  exposure  to  the  air.  Larocque  found  that  all 
the  tannin  contained  in  an  aqueous  solution  of  that  sub- 
stance, to  which  was  added  the  residue  of  the  preparation 


64  LEATHER  MANUFACTURE. 

of  tannin  from  gall  nuts  by  means  of  ether,  became  entirely 
converted  into  gallic  acid,  although  in  a  closed  vessel ; 
while  a  strong  solution  of  pure  tannin,  freely  exposed  to 
the  air  during  the  same  length  of  time,  contained  nearly 
the  whole  of  the  tannin  unaltered.  It  is  therefore  con- 
cluded that  the  insoluble  residue  of  the  nut-galls  contains  a 
substance  capable  of  acting  on  tannin  as  a  ferment,  and 
that  the  change  of  tannin  into  gallic  acid  in  such  cases  is 
a  species  of  fermentation.  This  is  rendered  still  more 
probable,  from  the  circumstance  that  the  vinous  fermenta- 
tion may  be  excited  in  grape  sugar  by  powdered  nut-galls 
which  have  been  digested  in  ether;  and  also  that  contact 
with  yeast,  blood  and  albumen,  produced  the  same  effect 
on  tannin  as  contact  with  the  residue  of  nut-galls,  though 
not  with  the  same  rapidity  as  the  latter.  The  gallic  acid 
formed  from  the  tannin  of  nut-galls,  through  the  agency 
of  yeast,  is  mixed  with  a  quantity  of  a  brown  bitter  sub- 
stance. 

Is  it  not  probable  that  while  tannin  exists  in  its  natural 
proportion  in  the  tanning  infusions,  that  it  prevents  the 
fermentative  decomposition  to  which  the  vegetable  matters 
would  be  susceptible  when  free  from  it,  and  that  when,  in 
the  ordinary  process  of  tanning,  the  skins  have  removed, 
by  absorption,  a  considerable  portion  of  the  astringent 
principle,  the  vegetable  matter  then  undergoes  decompo- 
sition, or  incipient  fermentation,  which,  when  once  set  in, 
proceeds  with  increasing  activity  ?  We  are  induced  to 
offer  this  suggestion  because  we  believe  that,  while  tannin 
exists  in  due  proportions  in  solution  with  the  vegetable 
matters  derived  from  the  plant,  gallic  fermentation  does 
not  take  place,  but  that  when  this  proportion  becomes 
reduced — either  by  the  action  of  the  oxygen  of  the  air, 
or  by  absorption  of  tannin  by  the  hides — fermentation 
supervenes. 

Checking  or  Preventing  Gallic  Fermentation. — 
Labaroque  has  observed  that  the  fermentative  decompo- 
sition of  tannin  may  be  prevented  or  checked  by  all  the 
antiseptic  substances  which  arrest  vinous  fermentation, 
such  as  aromatic  substances  and  volatile  oils,  and  soluble 


GALLIC  FERMENTATION.  65 

salts  of  mercury.  Corrosive  sublimate  is  said  to  prevent 
the  decomposition  most  effectually.  According  to  the 
same  authority,  the  presence  of  atmospheric  air  is  not 
essential  to  the  conversion  of  tannin  into  gallic  acid,  and 
no  appreciable  quantity  of  gas  is  liberated  during  the 
decomposition. 

It  has  been  proved  that  dilute  sulphuric  and  hydro- 
chloric acids  speedily  convert  tannin  into  gallic  acid 
without  contact  of  the  air,  when  the  mixture  is  exposed 
to  a  moderate  heat;  and  it  has  been  demonstrated  by 
M.  Antoine  that  the  decomposition  of  tannin,  when 
exposed  to  the  air,  is  not  at  all  accelerated,  but  rather 
retarded,  by  the  presence  of  a  very  minute  quantity  of 
either  of  the  above  acids,  provided  the  mixtures  be  kept  at 
the  ordinary  temperature.  Pyroligneous  acid  possesses 
the  property  of  retarding  the  decomposition  of  tannin  to 
a  very  considerable  extent,  probably  owing  in  a  great 
measure  to  the  presence  of  empyreumatic  bodies.  On 
the  contrary,  tartaric  and  malic  acids,  and  vegetable  acids 
in  general,  accelerate  the  decomposition  of  tannin.  The 
rapidity  with  which  sumac  ferments  may  be  referred  in  a 
great  degree  to  the  presence  of  a  considerable  quantity 
of  malic  acid  in  the  leaves,  according  to  some  analyses. — 
Pat-uell. 

"  From  the  preceding  observations,"  says  the  same 
author,  "  may  be  inferred  some  of  those  conditions  which 
the  tanner  should  endeavour  to  avoid  or  obtain,  in  order 
to  retard,  as  much  as  possible,  the  conversion  of  the  tan- 
ning principle  into  gallic  acid,  the  latter  being  incapable 
of  combining  with  gelatinous  tissue.  Though  the  obser- 
vations refer  particularly  to  the  tannin  of  gall  nuts,  which 
is  believed  to  be  the  same  kind  as  that  of  sumac,  yet 
there  is  every  reason  to  believe  that  they  are  applicable  to 
all  vegetable  substances  which  contain  a  variety  of  tannin, 
not  even  excepting  those  the  tannin  of  which  is  not  con- 
vertible into  gallic  acid  ;  for  all  kinds  of  tannin  are  sub- 
ject to  a  fermentative  decomposition,  though  the  different 
varieties  may  afford  very  different  products,  and,  in  all 
probability,  the  same  agents  which  possess  the  power  of 

F 


66  LEATHER  MANUFACTURE. 

restraining  the  fermentation  of  one  variety  would  that  of 
another.  An  idea  prevails  amongst  some  tanners,  how- 
ever, that  gallic  acid  exerts  some  beneficial  action  or  other 
in  the  process  of  tanning.  This  we  certainly  admit,  pro- 
vided the  ordinary  process  is  followed ;  but  undoubtedly 
it  is  at  the  expense  of  a  far  more  valuable  and  important 


agent. 


As  to  the  part  which  gallic  acid  performs  in  the  process 
of  tanning,  since  it  is  well  known  that  it  does  not  enter 
into  the  substance  of  the  skin,  so  as  to  form  a  constituent 
of  the  leather,  we  may  take  it  that  its  functions  are  of  a 
secondary  character,  merely  aiding  the  absorption  of  the 
tannin  by  swelling  the  pores  of  the  skin,  in  the  same  way, 
and  to  about  the  same  extent,  as  dilute  sulphuric  acid. 
If,  however,  the  hides,  after  liming,  have  been  raised  by 
the  dilute  mineral  acid,  it  is  difficult  to  conceive  that 
gallic  acid  performs  any  useful  part  in  the  operation  of 
tanning.  If  it  could  be  shown  that  this  acid  assisted  in 
promoting  the  combination  of  vegetable  extractive  with 
the  substance  of  the  skin,  its  importance  as  a  constituent 
of  tanning  infusions  would  be  readily  understood  and 
appreciated,  and  indeed  it  may  be  possible  that  in  some 
way  not  yet  understood  such  is  really  the  case. 

Knowing  that  the  oxygen  of  the  atmosphere  readily 
converts  the  tannin  of  tanning  infusions  into  gallic  acid,* 
may  we  not  conclude  that  the  process  of  handling  favours 
this  chemical  change  ?  The  skins,  while  supersaturated 
with  tan  liquor,  are  repeatedly  exposed  to  the  air,  and 
the  liquor  which  attaches  to  them,  as  also  that  which  flows 
from  them,  after  removal  from  the  pits,  necessarily  ex- 
poses a  very  large  superficial  surface  to  the  action  of  the 
air ;  and  it  is  not  reasonable  to  suppose  that  under  these 
conditions  a  considerable  portion  of  the  tannin  is  trans- 
formed into  gallic  acid  ?  If  this  be  so,  is  not  the  process 
of  handling,  as  at  present  conducted,  a  mistake  ? 

Is  not  the  system  of  suspension  preferable  ?  Against 
this  method  it  has  been  urged  that  after  a  while  the  tan- 
ning liquor,  by  remaining  stagnant,  suffers  decomposition ; 
*  Especially  when  other  organic  matters  are  present. 


GALLIC  FERMENTATION.  67 

tliis,  however,  could  be  checked  by  keeping  the  liquor  in 
gentle  motion  by  means  of  a  suitable  agitator,  by  which 
the  skins  would  be  constantly  exposed  to  fresh  surfaces  of 
the  liquor,  while  at  the  same  time  it  would  be  kept  in  an 
uniform  condition  until  the  whole  of  the  tannin  had 
become  absorbed,  when  the  spent  liquor  would  be  run  off 
and  replaced  by  fresh,  in  the  usual  way.  The  arrange- 
ments described  in  another  place,  would  appear  to  be  a 
feasible  plan  of  treating  skins  in  tan-liquor,  and  would, 
we  should  say,  render  the  process  of  handling  to  a  great 
extent  unnecessary. 

Carbolic  acid  has  been  frequently  used,  with  good 
effect,  to  check  gallic  fermentation  ;  pyroligneous  acid 
(wood  vinegar)  has  also,  as  we  have  said,  been  employed, 
but  since  its  action  is  believed  to  be  chiefly  due  to  the 
empyreumatic  matter  with  which  it  is  impregnated,  pro- 
bably commercial  wood  spirit  (pyroxilic  spirit),  in  small 
quantities,  would  have  a  similar,  if  not  a  more  powerful, 
effect,  since  it  contains  a  still  larger  quantity  of  empy- 
reumatic matter.  We  are  not  aware  if  this  substance  has 
been  tried,  but  are  disposed  to  think  that  a  few  experi- 
ments might  be  made  with  advantage.  Being  soluble  in 
water,  in  all  proportions,  there  would  be  no  difficulty  in 
applying  the  wood  spirit ;  the  quantity  used  must  be 
small,  however,  otherwise  it  will  impart  its  natural,  but 
not  disagreeable,  odour  to  the  leather;  this,  however, 
would  probably  disappear  during  the  treatment  of  the 
skins  in  the  layers. 


CHAPTER  VII. 
TANNING   MATERIALS. 

Sources  of  Tannin.— Barks.— Oak  Bark.— Barking  of  Trees.— Nut  Galls. 
— Tanning  Extracts. — Catechu. — Kino. — Gambler  or  Terra  Japonica. 
— Hemlock  Extract.— Chestnut  Extract. — Oakwood  Extract.— Larch 
Extract. — Quebracho  Extract. — Sumac. — Khatany  Boot. — Mangrove 
Extract. — Myrobalans. — Valonia. — Divi  divi. — Mimosa  Bark. — List 
of  Tanning  Materials. — Miscellaneous  Tanning  Materials. 

Sources  of  Tannin.  —  Since  the  period  when  Lewis, 
Deyeux,  Seguin,  Davy  and  others  investigated  the  princi- 
ples of  tanning,  the  vegetable  kingdom  has  been  industri- 
ously explored,  and  a  vast  number  of  plants  examined  to 
determine  the  presence  of  tannic  acid  and  its  proportion 
in  the  various  parts  of  trees,  shrubs,  and  herbs.  These 
researches  have  not  only  increased  our  knowledge  as  to  the 
wide  diffusion  of  the  important  proximate  principle, 
tannin,  but  have  also  developed  new  sources  from  which 
it  can  be  obtained  with  advantage  for  the  purposes  of  the 
tanner. 

The  sources  of  tannin  are  classified  under  the  following 
heads,  namely — 

Barks,  as  of  the  oak,  birch,  mangrove,  mimosa,  &c. 

Roots,  as  of  rhatany,  male  fern,  tormentil,  &c. 

Leaves,  as  of  sumac,  pomegranate,  tea,  &c. 

Excrescences,  or  gall  nuts. 

Extracts,  as  catechu,  gambier,  &c. 

Flowers  and  Fruits. 

Seed  pods. 

Barks. — One  of  the  most  important  sources  of  tannin  is 
the  bark  of  certain  trees,  but  more  especially  of  the  various 
species  of  oak,  willow,  hemlock  and  chestnut.  The  bark 


TANNING  MATERIALS.  69 

is  the  rind  or  exterior  covering  of  vegetables,  correspond- 
ing to  the  skin  of  animals.  It  consists  of  the  cuticle,  or 
epidermis,  the  parenchyma,  a  cellular  structure  containing 
colouring  matter,  &c.,  and  liber,*  the  inner  or  true  bark. 
This  last  is  formed  of  woody  fibre  in  great  quantity,  inter 
mixed  with  cellular  tissue.  At  the  commencement  of  the 
annual  growth  of  a  tree,  the  bark  separates  spontaneously 
from  the  wood,  in  order  to  make  room  for  the  new  matter 
forming  beneath.  It  thus  increases  by  yearly  layers,  and 
gradually  perishes  on  the  outside,  owing  to  toe  distension 
from  the  growth  of  the  inner  portion.  Its  physiological 
uses  are  numerous  and  important ;  it  is  the  depository  of 
many  of  the  secretions  of  plants,  and  it  acts  as  a  living 
filter,  separating  secretions  from  each  other,  and  allowing 
a  part  of  them  to  pass  off  horizontally  through  the  medul- 
lary processes  on  their  way  to  the  centre  of  the  tree.  But 
the  principal  offices  of  the  true  bark  appear  to  be  to  act  as 
a  protection  to  the  tender  wood,  and  as  a  channel  for  the 
sap  in  its  descent  from  the  leaves.  This  latter  function 
directs  attention  to  that  period  of  the  year  when  the  sap  is 
in  most  vigorous  circulation — the  spring,  at  which  time 
the  active  principles  deposited  in  the  cells  of  the  bark  are 
most  abundant.  For  example,  oak  bark  collected  in 
spring  contains  four  times  as  much  astringent  matter  as 
that  collected  in  winter. —  Coolcy.  With  few  exceptions, 
the  bark  is  more  easily  removed  from  a  tree  in  spring  than 
at  any  other  period  of  the  year.  When  a  tree,  or  one  of 
its  branches,  is  cut  across,  the  bark  is  easily  distinguished 
from  the  interior  layers  by  its  colour ;  and  if  we  examine 
the  bark  we  find  that  its  three  layers  are  perfectly  distinct, 
and  may  be  readily  separated. 

Oak  'Bark. — This  most  important  of  all  tanning 
materials  has  always  been  employed  by  British  tanners 
in  preference  to  any  other  ;  and  although  large  quantities 
of  tanning  materials  from  other  sources  are  consumed  in 
Great  Britain,  their  employ ment  is  rather  from  necessity — 
owing  to  the  weakness  in  tannin  of  oak  bark — than  from 

*  So  called  from  liber,  a  book,  because  in  the  early  ages  the  inner  bark 
was  stripped  off  iu  layers,  and  formed  into  leaves,  for  writing  upon. 


70  LEATHER  MANUFACTURE. 

choice.  Oak  bark  yields  its  tannin  under  the  most 
favourable  conditions  for  the  gradual  combination  of  the 
astringent  matter  with  the  tissue  of  the  skin,  and  at  the 
same  time  it  parts  with  its  extractive  matter  in  such  a 
way  that  by  slow  degrees  it  enters  into  the  substance  of 
the  skin,  and  doubtless  plays  an  important  part  in  the 
formation  of  sound  and  durable  leather. 

There  are  several  varieties  of  oak,  the  barks  of  which  are 
famous  for  their  richness  in  tannin,  amongst  which  may 
be  named  Qucrcus  robur,  Q.  coccifera,  Q.  subcr,  European 
varieties;  Q.falcata,  Q.rubra,  Q.  tinctoria,  &c.,  indigenous 
to  America.  "  The  bark  of  Quercus  robur — which  term  is 
applied  to  designate  a  group  of  closely -allied  species  or 
varieties,  and  of  which  the  Q.  pedunculata  and  Q.  sessili- 
flora  form  the  two  principal — is  generally  preferred  by 
the  tanner,  with  the  exception  of  Norway,  the  North  of 
Russia,  and  some  districts  in  France.  In  Norway  the 
birch  and  willow  are  resorted  to,  and  in  Russia  and  France, 
the  bark  of  other  species  of  oak,  the  Quercus  glomerata  and 
Q.  coccifera  are  occasionally  substituted.  The  latter 
variety,  known  also  as  the  kermes  oak,  is  a  tortuous, 
branching  shrub,  inhabiting  the  south  of  France,  Portugal 
and  Spain.  It  grows  to  the  height  of  three  or  four  feet, 
in  close  clumps,  the  roots  interlacing  one  another,  so  that 
the  soil,  which  might  otherwise  be  washed  away  by  the 
heavy  rains,  is  retained.  The  bark  of  the  root  of  this 
shrub,  whicL  is  sometimes  called  coppice  oak,  is  of  a 
yellowish-brown  hue,  and  very  rich  in  tannin.  It  is 
much  in  request  in  France  for  tanning  sole  leather  of  a 
superior  quality." — Muspratt. 

The  common  English  oak  (Q.  robur,  Linnaeus)  is  by 
some  botanists  named  Q.  pedunculata;  its  acorns  are 
borne  on  long  peduncles  (stems  supporting  the  fruit), 
and  is  thus  distinguished  from  Q.  sessiliflora,  which  has 
its  acorns  clustered  upon  a  very  short  stalk,  or  sessile 
(sitting),  with  leaves  on  elongated  stalks.  When  deprived 
of  its  epidermis,  it  is  of  a  light  brown  colour  externally  ; 
it  has  a  slight  odour,  but  the  taste  is  bitter  and  roughly 
astringent.  Its  properties  are  readily  extracted  by  water 


TANNING  MATERIALS.  71 

and  by  proof  spirit.  Its  constituents  arc  tannin  (about 
15  per  cent.),  gallic  acid,  uncrystallisable  sugar,  taimates 
of  lime,  magnesia,  potash,  &c.  The  inner  part  of  the 
bark,  as  before  observed,  contains  the  largest  proportion 
of  tannin. 

Barking  of  Trees. — Since  observation  has  proved  that 
tannin  exists  in  the  bark  of  trees  during  spring  time  to 
a  much  greater  extent  than  at  any  other  period  of  the 
year,  it  must  be  evident  that  great  care  is  necessary  to 
obtain  the  bark  when  it  is  in  a  condition  most  favourable 
to  the  requirements  of  the  tanner.  Until  the  subject  had 
been  thoroughly  investigated — and  in  this  the  careful 
researches  of  Davy  and  other  scientific  men  have  been  of 
immense  service  to  the  tanner — the  rind  of  old  oaks  was 
deemed  of  more  value  for  tanning  purposes  than  the  pro- 
duct from  younger  wood.  Experience,  and  a  more  in- 
timate knowledge  of  the  chemistry  of  the  subject,  have 
shown  that  not  only  does  the  bark  of  younger  wood  yield 
more  tannin  than  that  from  older  trees,  but  the  leather 
prepared  with  it  is  softer  and  whiter.  "  Doubtless  the 
best  age  at  which  the  trees  should  be  barked  is  from 
eighteen  to  twenty -five  or  thirty  years  ;  but  owing  to  the 
importance  of  the  timber  for  building  and  other  purposes, 
rarely  are  trees  of  this  age  felled  in  England  or  European 
countries.  In  France,  however,  they  harvest  the  bark  of 
the  oak  at  this  age,  but  the  wood  is  not  turned  to  further 
use,  excepting  for  the  manufacture  of  charcoal,  owing  to 
this  variety  not  being  adapted  for  the  builder.  In  France, 
too,  the  advantage  may  be  gained  of  collecting  the  bark  in 
the  spring,  at  a  time  when  the  sap  is  in  full  flow,  and 
when  there  is  most  tannin  contained  in  it ;  but  in  other 
countries,  where  the  bark  of  the  tree  constitutes  only  an 
inferior  secondary  product,  compared  with  the  wood,  this 
season  is  not  chosen,  in  consequence  of  the  timber  being 
cut  when  the  sap  is  in  active  circulation,  and  thus  less 
liable  to  decay." — Muspratt. 

The  period  for  debarking  the  trees  in  England,  Holland 
and  America,  is  about  June,  but  this  depends  upon  the 
mildness  of  the  winter  and  spring.  Barking  is  performed 


72  LEATHER  MANUFACTURE. 

by  cutting  two  circular  bands  round  the  trunk,  about  two 
or  three  feet  apart ;  a  longitudinal  strip  is  then  cut  from 
one  band  to  the  other  and  the  bark  loosened  at  the  upper 
band  and  stripped  off  by  means  of  peeling  irons,  the  bark 
being  beaten  when  necessary.  The  strips,  when  removed, 
are  spread  out  to  dry,  in  beds,  in  a  shady  situation,  and  they 
are  turned  over  occasionally  to  prevent  the  bark  from 
heating. 

The  harvesting  of  the  bark  requires  to  be  conducted 
with  great  care,  otherwise  not  only  will  the  bark  suffer 
loss  of  tannin,  but  also  produce  an  inferior  leather  in  the 
tan  pits.  Muspratt  observes,  "  For  the  most  part,  or, 
indeed,  in  all  cases,  the  bark  should  rest  on  hurdles 
elevated  more  or  less  from  the  ground,  in  an  inclined 
state,  and  the  fragments  ought  never  to  be  heaped 
together  more  than  twelve  to  eighteen  inches  in  thickness. 
Provision  ought  to  be  made  to  protect  the  bark  from  the 
rain,  and  the  whole  should  be  turned  at  least  once  a  week 
till  quite  dry.  After  this  it  is  usually  stacked  in  rect- 
angular heaps,  and  protected  by  thatch,  if  not  by  a  roof, 
from  rain  and  wet." 

In  the  year  1897  it  was  stated  that  about  40,000  tons 
of  oak  bark  was  annually  imported  into  England  from 
Germany,  the  Netherlands,  and  ports  in  the  Mediterranean, 
but  there  is  no  means  of  ascertaining  how  much  English 
oak  bark  is  obtained. 

Davy  gives  the  following  quantities  of  tannin  contained 

in  oak  bark  : — 
.,<•* 

480  Ibs.  of  entire  bark,  of  a  middle  sized  oak,  cut  in 

spring 29  Ibs. 

,,  coppice  oak  32    „ 

.,  oak  cut  in  autumn 21    „ 

White  cortical  layers 72    „ 

According  to  BraconnoJ,  oak  bark  contains,  besides  tannic 
acid,  tannates  of  the  earths,  gallic  acid,  pectin,  and  lignin. 

The  proportions  of  tannin  in  Elm,  Willow,  and  other 
barks,  &c.,  are  given  in  the  foregoing  table. 

Cork-tree  bark  is  obtained  from  Quercus  suber,  a  species 
of  oak  growing  in  Spain,  Tuscany,  and  the  islands  of 


TANNING  MATERIALS.  73 

Corsica  and  Sardinia,  and  on  the  northern  coasts  of 
Africa.  The  outer  layer  or  bark  of  the  tree  constitutes 
what  is  known  as  cork,  while  the  inner  layer,  which  is  of 
considerable  thickness,  is  procured,  from  its  richness  in 
tannin  (about  12  per  cent.),  as  a  tanning  material,  the 
greater  portion  of  which  is  employed  by  the  tanners  of 
Ireland. 

Nut-galls. — These  remarkable  excrescences,  which  con- 
tain a  large  percentage  of  tannin,  and  also  gallic  acid,  are 
imported  largely  into  England  from  Smyrna,  being  the 
produce  of  Asia  Minor ;  also  from  Aleppo,  the  produce  of 
the  vicinity  of  Mosul  in  Kurdistan,  a  province  of  Persia. 
They  are  also  imported  from  Bombay.  Besides  the  names 
applied  from  the  places  whence  they  are  obtained,  the 
Levant  galls  are  distinguished  by  their  physical  character- 
istics, being  called  Blue  or  White  galls.  The  Blue  galls 
vary  in  si/e,  and  are  of  a  bluish-grey  colour.  They  are 
gathered  before  the  insect  [Cynips]  becomes  fully  de- 
veloped, or  worked  its  way  out  of  the  nut.  Some  of  these 
are  larger,  and  are  called  Green  galls,  from  being  of  a 
greenish  colour.  They  exhibit  on  their  otherwise  smooth 
surface,  a  number  of  bluntly-pointed  tubercles,  which 
would  appear  to  be  the  apices  of  leaves  stimulated  into 
unnatural  growth.  The  best  galls  are  heavy,  hard,  and 
shining,  and  break  with  a  short  flinty  fracture.  White, 
galls  are  so  called  from  being  of  a  lighter  colour  than  the 
others,  but  still  of  a  greyish  or  yellowish  hue.  They  are 
distinguished  by  being  perforated  with  a  small  round 
hole,  by  which  the  insect  had  escaped.  They  are  usually 
less  heavy  than  the  others,  have  a  larger  internal  cavity, 
and  are  not  so  astringent.  A  third  variety,  called  Large 
Mecca  galls,  are  sometimes  imported  from  Bussorah  ;  they 
are  called  Dead  Sea  Apples,  and  Mala  insana.  They  are 
identical  with  some  specimens  brought  by  the  Hon.  E. 
Curzon  from  the  Holy  Land  in  1847.  They  are  spherical 
in  shape,  and  surrounded  about  the  centre  by  a  circle  of 
horned  protuberances.  They  are  astringent  like  other 
galls,  and,  when  fresh,  are  said  to  be  purple  and  shining. 
They  are  thought  to  be  the  produce  of  a  peculiar  variety 


74  LEATHER  MANUFACTURE. 

of  Quercus  infectona,  which  grows  on  the  mountains  near 
the  Dead  Sea.  Peculiar  galls  of  an  irregular  shape  have 
occasionally  been  imported  from  China,  where  they  are 
known  by  the  name  of  Woo-pei-tzee.  They  are  very 
astringent,  and  are  supposed  by  Dr.  Schenk  to  be  formed 
by  the  puncture  of  the  leaves  of  the  Rhus  semialata  (Tere- 
binthacas)  by  a  peculiar  species  of  Aphis. 

Tanning  Extracts. — Catechu. — This  important  tan- 
ning material  is  also  known  in  commerce  by  the  names 
Cashew,  Cutch,  Gambler,  and  Terra  Japonica  (J  apan  earth). 
Catechu  is  properly  an  extract  prepared  from  the  wood  of 
Acacia  Catechu,  but  the  term  is  now  applied  to  other 
extracts  similar  in  appearance  and  properties.  The  leaves 
of  the  Uncaria  gambir  yield  an  extract  which  is  known  in 
commerce  as  Terra  Japonica,  Gambir,  or  Gambler,  which 
is  prepared  in  square  pieces  or  blocks  (cube  gambier). 
The  acacias,  however,  are  most  famous  for  the  secretion 
of  astringent  matter  in  the  wood,  bark,  and  legumes  (seed 
vessels)  of  various  species,  from  which  the  catechus  of 
commerce  are  obtained.  Catechu  is  generally  in  square  or 
roundish  pieces  or  balls,  varying  in  colour  from  a  pale 
whitish  or  light  reddish  brown,  to  a  dark  brown  colour ;  it 
is  either  earthy  in  texture,  lamellated,  or  presents  a  smooth 
shining  fracture.  Some  kinds  are  more  friable  (easily 
crumbled)  than  others,  and  all  are  without  smell.  The 
taste  is  powerfully  bitter  and  astringent,  and  leaves  a  sweet 
after-taste.  The  pieces  are  generally  of  a  darker  colour 
externally  than  they  are  inside.  Some  kinds  are  covered 
with  rice  husks,  others  are  enveloped  in  leaves.  The  pale 
variety  is  usually  distinguished  from  the  dark  coloured, 
and  is  said  to  be  imported  from  Calcutta,  but  we  have 
obtained  both  kinds  in  the  bazaars  there,  the  pale  being 
imported  from  the  upper  provinces,  and  the  dark  from 
Pegu  and  Singapore.  The  dark  brown  catechus  are  ob- 
tained from  Bombay,  but  both  kinds  may  no  doubt  be 
prepared  from  the  same  tree,  as  a  greater  degree  of  heat, 
or  longer  continued  heat,  and  greater  exposure  to  light,  is 
said  to  produce  the  dark  colour.  The  dark  are  heavier, 
more  dense  in  texture,  and  have  a  resinous  fracture.  The 


TANNING  MATERIALS.  75 

largest  portion  of  good  catechu  is  taken  up  by  water, 
especially  when  boiling,  the  infusion  being  of  a  light  red 
or  reddish-brown  colour,  according  to  strength  :  it  reddens 
litmus,  and  is  strongly  astringent  in  taste.  It  yields  a 
precipitate  with  the  salts  of  ammonia,  also  with  acetate  of 
lead,  and  one  of  a  blackish-green  colour  with  the  salts  of 
the  sesquioxide  of  iron. — Dr.  Royle. 

Sir  Humphry  Davy,  in  analysing  the  dark  and  pale 
catechu,  or  those  of  Bombay  and  Bengal,  obtained  from — 

Insoluble 

Of  Tannin.     Extractive.    Mucilage.       Residuum. 
Dark  catechu  ..109       ..       68       ..       13       ..       10  =  200 
Palo        „         ..       97       ..       73       ..       16       ..       14  -  200 

The  principle  which  Davy  termed  extractive  has  since 
been  named  Catechinc,  or  Catechuic  acid.  This  is  most 
easily  obtained  by  treating  gambier  with  cold  water ;  the 
tannin  being  dissolved,  the  insoluble  residue  is  impure 
catechine,  which  may  be  purified  by  dissolving  in  alcohol 
and  subsequent  crystallisation,  when  it  has  the  appearance 
of  a  white  powder,  but  is  in  the  form  of  silky  needles,  of  a 
somewhat  sweetish  taste,  producing  a  green  colour  with 
salts  of  iron.  M.  Soubeiran,  who  made  a  series  of  experi- 
ments with  catechu,  came  to  the  conclusion  that  Pegu 
catechu  is  the  most  astringent  of  all  the  vegetable  astrin- 
gents ;  next  to  this,  in  astringency,  is  Jamaica  kino ;  next 
Amboyna  kino ;  fourth  on  the  list  is  Indian  catechu,  and 
fifth,  extract  of  rhatany.  8  parts  of  Pegu  catechu  are 
found  to  contain  as  much  tannin  as  10,  12,  14,  and  15 
parts  of  the  others  respectively. 

The  characteristics  of  the  principal  varieties  of  catechu 
are  as  follows : — 

Bombay  Catechu. — Firm,  brittle,  dark  brown,  of  a 
uniform  texture,  and  a  glossy,  semi-resinous  and  uneven 
fracture.  Specific  gravity,  1*39.  Richness  in  tannin,  52 
per  cent. 

Bengal  Catechu.  —  Rusty  brown  colour  externally ; 
porous,  and  more  friable  than  the  preceding.  Sp.  gr.  1*28. 
Richness  in  tannin,  49*5  per  cent. 

Malabar  Catechu. — Resembles  the  last  in  appearance, 


76  LEATHER  MANUFACTURE. 

but  is  more  brittle  and  gritty.  Sp.  gr.  1*40.  Richness 
in  tannin,  45*5. — A.  J.  Cooley. 

Kino,  or  Gum  Kino. — This  well-known  astringent  sub- 
stance is  described  in  the  British  Pharmacopoeia  as  "  the 
juice  flowing  from  the  incised  bark  of  the  Pterocarpus 
marsupium,  or  Indian  kino-tree,  hardened  in  the  sun ;  it 
is  also  the  concrete  juice  of  Pterocarpus  erinaceus  (in 
Africa),  and  of  other  undetermined  genera  and  species." 
From  the  uniformity  of  its  appearance,  it  would  appear  to 
be  the  natural  gummy  exudation  of  some  one  plant,  but 
several  kinds  of  kino  are  met  with  in  commerce  which  are 
known  to  be  the  products  of  various  plants,  as  that  of 
Butea  frondosa,  from  India,  Botany  Bay  kino,  produced 
by  Eucalyptus  resinifera,  or  brown  gum  tree,  also  a 
Jamaica  and  a  Columbian  kino,  and  sometimes  an  extract 
of  rhatany  has  been  included  in  the  list.  The  genuine 
kino  has  been  supposed  to  come  from  the  west  coast  of 
Africa,  but  it  is  understood  that  the  best  is  now  importe*d 
from  Bombay. 

Kino  is  in  small,  irregular,  somewhat  angular,  glistening 
fragments,  of  a  dark  brown  or  reddish-brown,  colour, 
brittle,  and  affording  a  powder  which  is  lighter  coloured 
than  the  masses.  It  is  without  odour,  and  has  a  bitterish, 
highly  astringent,  and  ultimately  sweetish  taste.  It  is 
not  softened  'by  heat ;  cold  water  dissolves  it  partially, 
boiling  water  more  largely,  and  the  saturated  decoction 
becomes  turbid  on  cooling,  and  deposits  a  reddish  sedi- 
ment. Alcohol  dissolves  the  greater  portion.  It  consists 
chiefly  of  a  peculiar  modification  of  tannin  and  extrac- 
tive matter,  and  in  some  of  the  varieties,  of  a  minute 
portion  of  resin. — Royle.  According  to  Yauquelin,  it 
contains  no  gallic  acid,  but  tannin  and  peculiar  extractive, 
75  ;  red  gum,  24  ;  insoluble  matter,  1.  Its  aqueous  solu- 
tion is  precipitated  by  gelatine  (with  which  it  produces 
a  gum,  in  consequence  of  the  presence  of  a  little  cate- 
chine),  by  salts  of  iron,  &c.  The  alkalis  favour  its  solu- 
bility in  water,  but  essentially  change  its  nature,  and 
destroy  its  astringent  property.  Soubeiran  states  that  kino 
contains  more  tannin  than  Indian  catechu,  but  less  than 


TANNING  MATERIALS.  77 

Pegu  catechu,  and  also  that  infusions  of  kino  and  Indian 
catechu  alike  produce  a  brown  colour  with  solutions  of 
perchloride  of  iron,  with  which  Pegu  catechu  forms  a 
green . 

Gambler,  Gambir,  or  Terra  Japonica  (Japan  earth)  is 
an  extract  from  the  plant  Uncaria  gambir — a  native  of 
Malacca  and  the  neighbouring  islands,  and  was  imported 
from  Singapore  in  1904  to  the  extent  of  about  1(30,280 
cwts.  It  occurs  in  the  market  in  the  form  of  bales  weigh- 
ing about  2  cwt.  each,  but  a  superior  article,  called  cube 
gambler,  comes  to  us  in  the  form  of  small  blocks.  For  a 
long  period  the  English  tanners  failed  to  understand  the 
proper  mode  of  employing  this  agent,  for  when  employed 
alone,  besides  imparting  a  dark  red  colour  to  the  leather, 
it  produced  a  soft  and  spongy  article.  It  is  now  better 
understood,  however,  and  is  much  employed,  in  moderate 
proportions,  in  the  preliminary  stages  of  tanning. 

Hemlock  Extract. — The  great  success  of  hemlock 
tanning  in  the  Northern  States  of  America,  has  led  to  the 
importation  into  this  country  of  large  quantities  of  an  ex- 
tract of  this  important  tanning  material,  which  is  exten- 
sively used,  in  combination  with  other  tanning  agents. 

Chestnut  Extract. — This  is  another  comparatively 
recent  tanning  material,  chiefly  imported  from  France, 
being  obtained  from  the  wood  and  bark  of  the  tree. 

Oakwood  Extract  is  now  also  very  largely  used  as  a 
tanning  agent,  as  also, 

Larch  Extract,  or  Hungarian  Larch  Extract,  which  is 
favoured  to  some  extent  by  English  tanners  of  light 
leathers. 

Quebracho  Extract,  from  the  bark  of  Aspidospermum 
quebracho,  is  also  now  largely  used  in  Britain,  Germany, 
and  America. 

Sumach,  or  Sumac. — This  much  esteemed  tanning 
material — especially  for  light  coloured  leathers — is  a 
powder  of  the  leaves,  peduncles,  and  young  branches  of 
Rhus  coriaria  and  R  cotinus  (wild  olive),  the  product  of 
the  former  being  employed  by  the  tanner,  more  espe- 
cially in  the  preparation  of  morocco  and  similar  leathers, 


78  LEATHER  MANUFACTURE. 

wliile  that  from  the  latter  is  used  in  dyeing.  Rhus 
coriaria  is  a  shrub  growing  wild  in  Portugal,  Spain, 
Italy,  Sicily  and  France,  which  countries  produce  con- 
siderable quantities  of  sumac,  varying  in  quality,  and 
distinguished  from  each  other  by  the  habits  of  the  plant, 
the  colour,  and  other  properties.  The  shrub  grows  to 
the  height  of  from  four  to  eight  feet,  with  a  crooked 
stem,  covered  with  a  reddish-grey  bark  ;  its  leaves  are 
green  on  the  upper  surface  and  of  a  whitish  colour  on  the 
under  surface  during  spring  and  summer,  but  they  acquire 
a  reddish  hue  in  autumn.  The  plant  flowers  in  July,  the 
blossoms  being  of  a  greenish-red,  and  it  yields  clusters  of 
small  crimson  berries. 

Sumac,  as  a  tanning  material,  is  chiefly  preferred, 
especially  on  the  Continent,  for  its  not  imparting  colour- 
ing matter  to  the  leather  prepared  with  it.  It  is  stated 
that  one  drawback  in  its  employment  is  that  it  deprives 
the  skin  of  much  of  its  softness  and  pliability.  In  the 
manufacture  of  morocco  and  glazed  leather  it  is  largely 
used ;  and  when  mixed  with  bark  or  other  tanning  material 
it  yields  very  good  results. 

Muspratt  says : — "  Of  the  species  of  sumac  in  the 
market,  the  Sicilian  is  accounted  the  best.  There  are  two 
kinds,  one  of  which,  the  Alcamo,  is  the  most  esteemed. 
It  is  a  very  fine  light  green  powder,  containing  very  little 
woody  matter,  having  an  agreeable  odour,  analogous  to 
that  of  the  violet,  and  a  strong  astringent  taste ;  it  con- 
tains very  little  colouring  matter,  though  it  gives  a  yel- 
lowish-green solution  when  macerated  with  water.  The 
second  variety  inclines  to  a  reddish  yellow,  has  a  feeble 
odour,  with  a  less  astringent  taste  than  the  foregoing 
variety.  On  this  account  it  is  not  much  employed  in 
tanning,  though  extensively  used  in  dyeing.  Sicilian 
sumac  is  generally  packed  in  bales  weighing  about  one 
and  a  half  hundredweight.  Spanish  sumac  is  various  in 
quality,  being  less  carefully  prepared,  and  consequently 
more  or  less  mixed  with  woody  matter.  The  best  sort 
comes  from  Priego,  and  is  grown  in  the  neighbourhood  of 
Malaga.  It  is,  like  the  Sicilian,  finely  ground,  and 


TANNING  MATERIALS.  79 

affords  a  colour  of  equal  or  greater  brightness .;  its  odour 
reminds  one  of  the  tea  plant.  With  water  it  gives  a  dark 
and  more  reddish  solution  than  the  foregoing.  It  is 
usually  packed  in  bales  of  one  cwt.  The  other  sorts, 
Molina  and  Vulladolid  sumac,  are  next  in  quality  ;  they 
are  very  similar.  Portuguese,  or  Porto,  sumac  is  almost 
similar  to  the  Priego,  but  is  generally  dirtier,  and  con- 
tains more  mineral  salts.  Italian  sumac  has  a  dark 
brown  colour,  is  free  from  woody  matter,  but  feels  granular 
in  the  hand,  and  has  an  odour  like  that  of  the  bark,  which 
possesses  similar  qualities  to  the  leaves.  French  sumac  is 
similar  to  the  preceding.  Three  sorts  are  collected.  The 
Faucis  is  almost  equal  to  the  Sicilian  when  well  purified, 
and  comes  from  Brignolles,  near  Marseilles.  If  less  care 
be  taken  in  its  manufacture  it  approaches  more  to  the 
quality  of  Malaga  sumac ;  it  frequently  goes  under  both 
these  names.  A  second  sort,  Donzeri,  and  a  third,  Pudis, 
are  commonly  used  in  the  tanneries.  A  fourth  variety, 
called  rodou  or  rddoul,  obtained  from  the  Coriaria  myrii- 
folia,  cultivated  in  Languedoc,  is  of  a  greyish-green 
colour. 

The  method  of  preparing  sumac  for  the  market  con- 
sists in  collecting  the  twigs  of  the  shrub  whilst  in  full 
foliage  and  drying  them  in  the  sun.  The  leaves  are  after- 
wards separated  by  threshing,  and  are  then  collected  and 
ground  under  mill-stones  ;  the  powder  is  then  packed  in 
bales  for  the  market.  Sometimes  the  peduncles  and  more 
tender  shoots  are  ground  with  the  leaves,  but  since  these 
portions  of  the  shrub  contain  a  good  deal  of  tanning  prin- 
ciple they  do  not  much  detract  from  the  quality  of  the 
material. 

Rhatany  Boot. —  The  rhatany  plant  (Krameria  tri- 
andria)  is  a  native  of  Peru,  where  it  grows  on  the 
slopes  of  the  sandy  mountains,  more  particularly  near 
Huanuco,  where  it  was  discovered  by  Ruiz,  who  found 
that  the  root  was  employed  by  ladies  for  rubbing  the  teeth 
and  strengthening  the  gums.  The  root  is  woody  and 
branched ;  the  pieces  vary  from  an  inch  to  the  size  of  a 
quill.  The  cortical  part  is  reddish-brown,  fibrous,  and 


80  LEATHER  MANUFACTURE, 

easily  separated  from  the  central  reddish-yellow  woody 
part.  The  root  is  without  smell,  but  has  an  extremely 
astringent  taste  without  being  bitter.  The  cortical  por- 
tion contains  a  much  larger  percentage  of  the  active 
principle  than  the  interior  ;  the  smaller  pieces  from  the 
greater  proportion  of  the  bark  are  the  most  rich  in  tannin. 
An  extract  is  sometimes  imported  from  South  America. 

Hhatany  root  consists  of  one-third  matters  soluble  in 
water;  these  consist  of  tannin,  42*6;  gallic  acid,  0'3; 
gum,  extractive  and  colouring  matter,  56'6 ;  and  krameric 
acid,  0*5.  Water  and  alcohol  both  dissolve  its  active  pro- 
perties, forming  a  reddish  solution.  According  to  Gmelin 
and  Peschier,  rhatany  root  yields  : 

Gmelin.  Peschier. 

Tannin    38'3  42-6 

Gallic  acid 0-3 

Sweet  matter 6*7  — 

Nitrogenous  matter 2-5 

Mucilage     8-3  — 

Lignin     433 

Krameric  acid   0'4 

Gum,  extractive,  and  colouring  matter  56*7 

99-1  100-0 

Mangrove  Extract. — Of  late  years  much  attention 
has  been  devoted  to  mangrove  bark  and  its  extract. 
The  mangrove  species  is  found  growing  in  swamps  in 
most  tropical  parts  of  the  world,  the  tannin-yielding 
trees  being  known  as  Rhizophora  mangle,  and  other  allied 
species.  The  trees  grow  in  the  tidal  districts  of  East 
India  and  Borneo  freely,  and  of  late  years  several  extract- 
ing plants  have  been  installed  in  the  latter  country,  and 
the  tannin  extract  exported  in  the  form  of  a  dry  crystal- 
live  product  known  under  various  fancy  names.  The 
percentage  of  tannin  contained  in  the  bark  varies  con- 
siderably, some  going  as  high  as  45,  whilst  others  yield 
only  5  per  cent.  The  catechol  tannin  is  easily  extracted, 
but  is  of  a  deep  reddish  tint,  which,  when  used  alone, 
makes  an  objectionable  coloured  leather.  The  extract 
contains  from  60  to  70  per  cent,  of  tannin,  and  much  of 
the  colour  is  eliminated  in  the  course  of  manufacture. 


TANNING  MATERIALS.  81 

It  is  one  of  the  cheapest  forms  of  tannin  now  on  the 
market,  and  bids  fair  to  become  very  popular. 

Myrobalans  (also  called  My rabolams). — The  myrobalau 
is  the  fruit  of  several  species  of  Terminalia,  namelv  Tenni- 
nalia  chebula,  T.  bellerica,  T.  citrina,  and  Kmblica  qfficinalis  ; 
these  trees  abound  in  Ilindostan,  Ceylon,  Burmah,  &c. 
The  myrobalan  varies  in  size  from  that  of  a  small  hazel 
nut  to  that  of  the  nutmeg.  The  tannin  occurs  in  the  pulp 
which  surrounds  the  kernel.  When  employed  alone  in 
tanning,  myrobalans  deposit  a  considerable  quantity  of 
bloom  or  ellagic  acid ;  they  are,  however,  generally  used 
in  combination  with  other  tanning  materials,  from  their 
usefulness  in  modifying  the  objectionable  colour  which 
some  of  the  latter  impart  to  leather  prepared  with  them. 
Owing  to  the  extreme  hardness  of  the  nut,  or  stone,  it 
requires  to  be  ground  by  a  mill  specially  constructed  for 
the  purpose. 

Valonia. — This  name  is  given  to  the  calyx,  or  cup,  of 
a  large  acorn,  the  fruit  of  a  species  of  oak,  Quercus  teyilopx, 
which  abounds  in  Asia  Minor,  Roumelia,  and  Greece. 
Some  botanists  have  recognised  other  varieties  of  Valonia 
oak,  as  Qncrcus  macrolrpis  and  Q.  stcnophylla,  growing 
in  the  Greek  peninsula.  The  largest  supply  of  valonia, 
however,  comes  from  Smyrna.  It  has  been  stated  that 
Palestine  abounds  with  the  valonia  oak,  and  the  late  Mr. 
Sparke  Evans  thought  that  it  might  be  successfully 
grown  in  Australia,  and  thus  become  a  source  of  wealth 
to  that  colony,  which,  possessing  neither  large  rivers  nor 
extensive  forests,  has  more  need  to  cultivate  shrubs  of 
commercial  value.  The  suggestion  is  a  good  one,  and 
deserves  to  be  further  promulgated. 

In  an  interesting  paper  in  the  Tanners9  Journal  respect- 
ing valonia,  the  writer  gives  some  very  useful  informa- 
tion, from  his  own  personal  observation,  from  which  we 
extract  the  following:  "The  fruit  begins  to  ripen  in  July, 
and  is  ready  for  the  cultivator  in  August.  Some  small 
portion  of  it  never  attains  maturity,  and  either  falls  off 
the  trees  of  itself,  or  is  beaten  off  in  the  shape  of  camata 
or  camatina.  These  two  trade  terms  signify  those  cups 


82  LEATHER  MANUFACTURE. 

that  have  not  opened  fully,  and  remain  with  the  acorn 
stunted,  and  so  embedded  in  them  that  it  cannot  be 

extracted The  acorns  which  grow  in  the  cups  are 

gathered  with  them,  but  the  knocking  about  which  the  fruit 
is  subjected  to  before  it  is  finally  despatched  to  Smyrna,  and 
the  mere  fact  of  drying,  suffice  to  detach  a  great  number 
in  the  meanwhile,  and  the  produce  thus  reaches  our 
market  with  only  a  small  portion  of  them.  The  valonia 
is  put  into  sacks,  and  is  then  forwarded  by  camels  to  the 

nearest   railway   station The   valonia,    having 

reached  Smyrna,  is  emptied  into  dry,  commodious,  and 
well- aired  stores  specially  built  here  for  the  article,  and 
then  undergoes  the  process  of  picking  and  cleaning.  This 
is  done  principally  by  \vomen,  children,  and  infirm  old 
men  incapable  of  hard  work.  The  smaller,  or  '  spine/  is 
separated  from  the  cups,  which  are  placed  apart.  The 
former  is  always  mixed  with  a  proportion  of  earth  and 
stones  collected  with  the  fruit  from  the  ground,  and  has 
to  be  freed  from  this  extraneous  substance.  The  cups  are 
placed  in  large  heaps  before  the  cleaners,  who  rapidly 
lay  aside  all  the  damaged  cups  and  all  the  acorns,  and 
push  the  remainder  behind  them  with  their  hands  after 
thus  cleaning  it.  At  the  same  time  the  Trieste  cups  are 
quickly  thrown  into  separate  baskets,  and  the  valonia 
thus  leaves  the  workers'  hands  in  three  distinct  qualities — 
Mezzana,  English,  and  refuse.  The  first,  however,  which 
consists  of  the  finest  large  cups,  is  not  picked  out  of  all 
parcels.  In  many  cases  it  is  allowed  to  remain  in  the 
English  quality,  which  then  takes  the  name  of  *  natural/ 
from  the  fact  of  its  thus  containing  all  the  sound  cups 
originally  produced."  From  this  it  will  be  seen  that 
valonia  of  the  second  quality  only  is  exported  for 
England. 

Divi  divi  is  the  pod  of  a  leguminous  shrub  (Ccesalpinia 
coriaria),  a  native  of  South  America  and  some  other 
tropical  countries ;  it  is  also  cultivated  in  Madras,  Hin- 
dostan,  Ceylon,  and  other  parts  of  India.  The  tannin  of 
the  seed-pod  exists  in  the  tissue  beneath  the  epidermis, 
the  seeds  themselves  yielding  no  tanuin.  The  tannin  is 


TANNING  MATERIALS.  83 

generally  extracted  by  boiling  the  material  in  separate 
pits,  while  others  crush  the  pods  in  a  mill,  and  employ 
them  as  dust  for  the  handlers.  The  employment  of  divi 
divi  in  the  tannery,  however,  appears  as  yet  to  be  but 
imperfectly  understood.  Containing,  sometimes,  nearly 
50  per  cent,  of  tannic  acid,  it  should  be  a  valuable  tanning 
agent ;  but  since  it  also  possesses  a  considerable  propor- 
tion of  mucilaginous  and  oily  matter,  it  is  very  susceptible 
of  fermentation,  especially,  it  is  stated,  in  warm  weather, 
or  when  the  atmosphere  is  subjected  to  electrical  disturb- 
ance. The  late  Mr.  Sparke  Evans  said  :  "  This  causes,  at 
times,  much  annoyance  and  some  loss,  as  one  of  our  Bristol 
tanners  found  to  his  cost,  when  one  day,  passing  through 
his  drying  shed,  ho  came  to  a  pile  of  divi-tanned  butts, 
which  had  been  laid  down  to  temper,  but  through  which 
he  was  able  to  thrust  his  walking  stick  as  through  a 
honeycomb.  Divi-tanned  leather  feels  firm  in  dry,  but 
soft  in  damp  weather.  A  fortune  is  open  to  any  one 
who  can  employ  this  article  in  tanning  and  prevent 
the  dark  colour  which  accompanies  its  use."  To  check 
the  fermentation  to  which  divi  divi  is  specially  liable, 
acetic  acid,  and  more  recently  carbolic  acid  and  salicylic 
acid  have  been  used;  a  preparation  called  Antigalline 
has  also  been  used  with  some  degree  of  success. 

Mimosa  Bark. — This  material  is  obtained  from  various 
species  of  Acacia — an  extensive  family,  of  which  the  well- 
known  Sensitive  plant  is  a  remarkable  member.  The  spe- 
cies from  which  the  mimosa  of  commerce  is  derived  are  : — 
Acacia  molissitna,  A.  decurrens,  A.  pycant/ia,  A.  dealbata, 
and  some  others.  The  acacias  abound  in  Australia  and 
Tasmania,  and  large  quantities  of  the  bark  are  exported 
to  this  country — by  far  the  greatest  quantity,  however, 
coming  from  the  former  colony.  Mimosa  is  generally 
chopped  or  ground  previous  to  exportation,  and  it  has 
also  been  introduced  in  the  form  of  an  extract.  The 
bark  contains  varying  proportions  of  tannic  acid,  the 
mean  being  about  24  or  25  per  cent.  Being  exceed- 
ingly hard,  the  bark  requires  to  be  very  finely  ground 
to  extract  all  its  tannin.  It  makes  a  red  leather,  and 

^^A.>  •<>    xv 

/         OFT"£        ,   A 
f    UNIVERSITY-  1 


LEATHER  MANUFACTURE. 


is   frequently  used   with  valonia   to   correct   the   colour 
produced  by  the  latter. 

LIST  or  TANNING  MATERIALS. 


Common  Name. 

Botanical  Name. 

Part  of 
Plant  vsed. 

Where  from. 

Pliylanthus  emblica   .  . 

Seed  pod 

Bengal. 

Aleppo  Pine  .  . 
Alder 

Pinus  excelepensis  .... 

Bark  .... 
Bark  .... 

Spain. 
Gt.  Britain  and  Spain. 

Pi'osopis  pollida 

Seed  pod 

South  America. 

Almardelboom 
Aru  iimtii 

Beabejiim  stellatum  .  .  . 

Bark  .... 
Bark  .... 

Africa. 
Australia  and  Tasmania. 

Arok  ken  em  a 

Bark  

Australia  and  Tasmania. 

Arrasa 

Bark  .... 

British     Guiana      and 

Extract  .  . 

West  Indies. 
Bengal. 

Babool 

Acacia  avabica  

Bark  .... 

Hindostan. 

Balsamo     .... 
I3aramalli     or 

Carpon  brevifolium    .  . 

Seed  pod 
Bark  .... 

South  America. 
West  Indies. 

pump  wood 
Bearberry  .... 
Betel 

Arctostaphilos  uva  tirsi 
Areca  cutechu  

Leaves    .  . 
Nut     .... 

Russia. 
East  Indies. 

Birch 

Betula  alba  . 

Bark     .  . 

Russia. 

Black  wattle  .  . 
Black  wood   .  . 

Acacia  mollissima  .... 
Acacia  melanoxylon  .  . 

Bark     .  .  . 
Bark     .  .  . 
Bark     .  .  . 

Australia  and  Tasmania. 
Australia  and  Tasmania. 
West  Indies. 

Blue  gum  .... 
Boomah 

Eucalyptus  globulus  .  . 
Pyenocatna  macrophylla 

Bark     .  .  . 
Nut  

Australia 
Africa. 

Butea-kino 

Extract  .. 

Bengal. 

Bark  .... 

South  America. 

Catechu       . 

Acocia  catechu  

Extract  .  . 

Bengal. 

Celery  Pine   .. 
Cherry  tree   .  . 
Chestnut    .... 

Phyllocladus      aspleni- 
folia 
Exocarpus      cupressi- 
formtis 

Bark  .... 
Bark  .... 
Bark  and 

Australia  and  Tasmania 
Australia  and  Tasmania. 
N.  America  and  Spain. 

Cevil 

Extract 
Bark  .... 

South  America. 

Couruda  

Avicennia  nitida    .... 

Bark   .... 

British     Guiana      and 

Cork  tree   .... 

Quercus  suber  

Bark  . 

West  Indies. 
Spain,  Italy. 

Crab  wood  .... 

Carapa  guianensis  .... 

Bark  .... 
Bark  .... 

West  Indies. 
South  America 

Cutch 

Acacia  catechu 

Extract  .  . 

Bengal. 

Cuyama  

Bark  

West  Indies. 

Deritelaria  .... 
Divi  divi    .... 

Doomboom     , 

Plumbago  europcea  .  .  . 
Casalpinia  coriaria  .  . 

Brk.ofroot 
Seed  pod 
Bark  . 

Fiance. 
South  America. 
South  Africa. 

TANNING  MATERIALS. 


Common  Name. 

Botanical  Name. 

Part  of 
Plant  used. 

Where  from. 

Galls   
Gambler  (Terr 

Quercus  infcctoria  .  .  .  . 
Uncaria  gainbir 

Gall  nuts 
Extract 

Turkey. 

Japonica) 
Gaub 

Diospyros  glutinosa   .  . 

Hoot 

Hindostan 

Hemlock    .  .  . 
Hemlock    ... 

Ilinan    .  . 

Abies  canadensis 
Geranium  inaciilatmn 

Elaocarptts  dentatiis  .  . 

Bark   ... 
Root     am 
Extract 
B;irk    and 

North  America. 
North  America. 

New  Zealand. 

Horr  plum 

Extract 
Dark     . 

British      Guiana     and 

Holm  tree    or 

Quercut  ilex    ....... 

Bark 

West  Indies. 
Italy 

Green  On  k 
Honeysuckle. 
Huldi  

Eanksia  auslralis  .... 

Burk  . 
Bark   

Australia  and  Tasmania. 
East  Indies. 

Iron  bark  .  .  . 
Ivuraralli 

Eucalyptus  resinifcra 
Lecythis  ollaria  

Extract  .  . 
Bark  .... 

Australia  and  Tasmania. 
British      Guiana     and 

Extract  .. 

West  Indies. 

Kermes  Oak  .  . 
Kino  

Quercus  coccifcra    .... 
Pterocarpus  martupium 

Bark   .... 
Extract  .  . 

France. 
Africa. 

Knoppern  .... 
Krupelboom  .  . 

Kullaballi  .... 

Quercut  pubescent  .... 
Lciicospermum      cone- 
carpum 

Galls  .... 
Bark  .... 

Bark  . 

Italy  and  Hungary. 
Africa. 

Larch  

Lorix  anicricana    .  . 

Bark 

Russia,  N.  America. 

T^dfix  €uropccn  ..... 

Bnrk 

Great  Britain 

Exlract    . 

Borneo  East  Indies. 

Marsh     Rose- 

Root  .... 

Russia. 

mary 
Mimosa 

Acacia  molissiina  .... 

Extract  .  . 

Queensland,  Victoria, 

Acacia  decurrcns  . 

and  Tasmania. 

Mochrus    .... 
Molle  

Bombax  makbarica    .  . 

Extract  .. 
Leaves    .  . 

Bengal. 
South  America. 

Mora  .  .  . 

](Iora  cxcelsa  

Bark 

British      Guiana     and 

Murici    

Bark  .... 

West  India. 
South  America. 

Myrobalans 

'J'tTtninalid  citrina     , 

Hindostan. 

Myrobalans  .  . 
Myrtle    . 

Terminalia  cherbufa  .  . 
Faytts  Cunniny/iatni 

Fruit  .  .  . 
Hark  

Hindostan. 
Australia  and  Tasmania. 

Myrtle    

Rhns  myrtifolia       .  .  . 

Bark  

Italy. 

Neb  neb  . 

Acacift  nilotica 

Seed  pod 

Africa,  Nubia. 

Oak     . 

Quercus  pcdunculata  .  . 

Bark  .... 

Great  Britain. 

Oak    

Quercut  sessiliflora  .  .  . 

Bark  .... 

Great  Britain. 

Olive  

Olea,  europoca  

Bark  .... 

Italy. 

Palachy  

Extract  .  . 

East  Indies. 

Pomegranate 
Puriuibaa  .... 

Punica  granatum   .... 

l-'usdfmis  comprcssus  .  . 

Fruit  shell 
Bark  .... 

Hindostan. 
Africa. 

LEATHER  MANUFACTURE. 


Common  Name. 

Botanical  Name. 

Part  of 

Plant  used. 

Where  from. 

Quebracho  .... 

Quercitron     .  . 
Red  birch.  .... 
Red  birch  
Red  birch 
Rhatany    .... 
Saffron  

Aspidospermum    que- 
bracJio 
Quercus  tinctoria   .... 
Coriaria  ruscifolia  .  .  . 
Eugenia  maire     .  .    .  . 

Bark  .... 

Bark   .... 
Bark  .... 
Bark   
Bark  
Root   
Bark  .... 
Bark   .... 
Bark   .... 
Bark  .... 

Bark  . 
Bark  .... 
Bark  .... 

Bark  . 
Bulb  .... 
Root   

Bark  .... 
Bark  .... 
Leaves  and 
twigs 
Galls  .... 
Bark  .... 
Bark  .... 

Bark  
Seed  pod 
Extract  .  . 
Root  
Bark  .... 
Bark  .... 

Bark  .... 
Acorn  cup 
Bark  .... 
Root  

Bark  .... 

Bark  .... 
Bark  .... 

South  America. 

North  America. 
New  Zealand. 
New  Zealand. 
New  Zealand. 
South  America. 
Africa. 
Australia  and  Tasmania. 
East  Indies. 
British      Guiana     and 
West  Indies. 
Australia  and  Tasmania. 
Australia  and  Tasmania. 
British      Guiana      and 
West  Indies. 
East  Indies. 
Africa. 
Russia,  North  America 

Spain. 
Hindostan. 
France,  Italy. 

East  Indies. 
New  Zealand. 
North  America. 

Australia  and  Tasmania. 
East  Indies, 
Bengal. 
Spain. 
New  Zealand. 
South  America. 

Hindostan. 
Turkey. 
Africa. 
North  America. 

South  America. 

France. 
France. 

Krameria  triandria  .  . 
Crocoxylon  excelsum  .  . 
Atherosperma  moschata 
Shorea  robusta   

Sassafras    .... 
Saul  tree    .... 
Seaside  grape 

She  oak  

Coccolobd  uvifera 

Casuarina  quadrivalvis 
Acacia  deu-lbata 

Silver  wattle.  . 
Sirnabelli  

Sogah  

Nectandra      

Squills    

Sdllct  vnavititnct  

Statice,orMrsh. 
rosemary 
Stone  pine.  .  .  . 
Subaujuna.  .  .  . 

Statice  coriaria  
Pinus  pinea    

Moringa  pterygosperma 
Rhus  corittiTid  

Tamarisk  galls 

Tamarix  indica  .... 

Tarsekeha  .... 

Tasman.  laurel 
Terce    

Phyllocladus      tricho- 
manoides 
Anopterus  glandulosa 
C&salpinia  

Terra  Japonica 
Tormentil  .... 
Towhai  

Tlncaria  gambit" 

Tormentilla  potentilla 
Weinmannia  racemosa 
Stryphnodendron   bar- 
batemas 
Cassia  atiriculata,   .... 

Tuga  veca  .... 

Wagen  boom. 
Water    plain- 
tain 
"White      man- 
grove 
Willow  
Willow  

Protea,  grandiflora  .... 
Polygonum  amphibiutn 

Avicennica  tormentosa 
Salix  ttlbct  .......... 

Salix  cinerea,  

Miscellaneous  Tanning  Materials. — The  shell  of  the 
seed  of  Sapindus  emarginatus,  an  East  Indian  plant,  is  said 


TANNING  MATERIALS.  87 

to  contain  31  per  cent,  of  tannin.  Samples  of  the  African 
gall  nut  of  Tamaria  are  said  to  contain  56 J  per  cent,  of 
tannin.  The  bark  of  Tamaria  gallica  gave,  on  analysis, 
3*52  per  cent,  of  tannin,  and  the  bark  of  Tcrminaliafor- 
mcntosa,  of  the  same  family  as  that  from  which  myrobalans 
are  obtained,  is  reputed  to  yield  26  per  cent,  of  tannin. 
The  bark  of  the  common  alder  (Alnus  glutinosa]  is  said  to 
yield  about  16  per  cent,  of  tannin.  The  Eucalyptus  leu- 
coxylon,  or  iron-bark  of  Victoria,  yields  about  22  per  cent, 
of  kinotannic  acid  ;  Eugenia  Smithii,  or  Australian 
myrtle-tree,  is  said  to  contain  17  per  cent,  of  tannic  acid, 
with  from  3  to  4  per  cent,  of  gallic  acid.  The  shells  of 
the  pomegranate  fruit  yield  about  13  per  cent,  of  tannic 
acid. 


CHAPTER  VIII. 
ESTIMATION  OF  TANNIN. 

.Examination  of  Bark. — Determination  by  Specific  Gravity. — The  Barko- 
meter. — Chemical  Methods  of  Estimating  Tannin. — Davy's  Method. — 
Bell  Stephens' Method. — Hammer's  Method.— LowenthaTs  Method. — 
Mr.  Hewitt  on  Lowenthal's  Method. — Mr.  Procter  on  Lowenthal's 
Method. — Ramspao.ker's  Method.  The  Tanuometer. — Casali's  Pro- 
cess.— Standard  Method.  —  International  Association  of  Leather 
Trades'  Chemists. 

WHEN  we  consider  the  vast  number  of  tan-yielding  vege- 
tables which  have  been  brought  to  the  tanner's  notice  since 
the  days  when  Davy  first  investigated  the  subject,  the 
variable  characteristics  of  the  different  tannins,  as  shown  by 
Gmelin,  Stenhouse,  Procter,  and  others,  and  the  difference 
in  the  percentage  of  tannin  in  the  various  plants,  or  parts  of 
plants,  which  enter  the  market  for  his  use,  it  will  at  once 
become  evident  that  the  tanner  should  be  in  possession  of 
some  means  by  which  he  may  estimate  the  true  value  of 
all  tanning  materials  with  which  he  may  have  to  deal. 
Moreover,  when  it  is  borne  in  mind  that  the  proper  condi- 
tion of  the  tanning  material  may  be  seriously  affected  by 
damp  or  long  exposure  to  the  air,  by  which  its  active 
principle  becomes  converted  into  a  product  useless  to  the 
tanner,  it  is  of  the  highest  importance  that  the  true  per- 
centage of  the  active  principle  (tannin)  should  be  deter- 
mined from  a  fair  or  average  sample,  before  the  bulk  of 
the  material — no  matter  from  what  source — is  purchased 
and  paid  for. 

With  a  view  to  aid  those  who  may  desire  to  test  the  value  of 
their  tanning  materials,  we  purpose  giving — as  free  as  pos- 
sible from  unexplained  technicalities — some  of  the  methods , 
adopted,  commencing  with  those  of  the  most  simple  cha- 


ESTIMATION  OF  TANNIN.  89 

racter.  Before  doing  so,  however,  it  may  be  well  to  con- 
sider what  are  the  proper  physical  characteristics  of  the 
leading  tanning  material — oak-bark. 

Examination  of  Bark.— The  bark  is  usually  in  long 
strips,  of  a  coarse  fibrous  texture,  and  not  easily  reduced  to 
powder.  When  deprived  of  its  epidermis,  it  is  of  a  light 
brown  colour  externally.  The  odour  is  f'uint,  but  the  taste 
bitter  and  very  astringent. — Roylc.  A  good  bark  is 
known  by  its  colour.  The  most  highly  esteemed  is  that 
which  is  white  outside  and  reddish  inside,  rough  and  dry 
on  the  side  of  the  wood,  breaks  easily,  and  gives  less 
ligneous  (woody)  matter  ;  the  taste  most  astringent  with  a 
strong  smell  when  ground.  A  sign  of  bud  quality  is 
when  the  epidermis  and  cortex  (bark)  are  very  thick 
and  have  a  blackish  colour ;  in  this  case  the  bark  is  too 
old,  and  has  experienced  the  commencement  of  decay. 
It  is  the  same  with  bark  which  has  been  left  a  long 
time  exposed  to  rain.  The  inner  side,  which  should  be 
reddish,  has  lost  its  colour,  and  the  other  parts,  which 
have  become  darkened,  have  lost  a  part  of  their  property. 
— Dussauce. 

Determination  by  Specific  Gravity. — It  is  well  known 
that  in  all  arts  in  which  solutions  of  chemical  sub- 
stances of  various  degrees  of  strength  are  employed,  the 
approximate  strength  of  the  solutions  is  determined 
by  means  of  an  instrument  called  a  hydrometer.  This 
instrument  consists  of  a  long  glass  tube  with  a  small 
bulb  partly  filled  with  mercury  or  small  shot  at  its  lower 
end,  and  a  somewhat  larger  bulb  at  a  short  distance  above 
the  mercury  bulb.  A  graduated  paper  scale  is  enclosed 
in  the  longer  stem  of  the  tube,  whicn  is  divided  into  tenths. 
When  the  hydrometer  is  floated  in  distilled  water,  it  sinks 
to  the  top  of  the  scale,  which  is  marked  1,000  orO  (zero) — 
the  specific  gravity  of  water.  This  is  taken  as  the  standard  by 
which  the  specific  gravity  of  all  other  fluids  is  determined. 
Since  alcohol  and  ether/however,  are  lighter  than  water, 
it  is  evident  that  such  an  instrument  would  not  be  of  ser- 
vice in  determining  their  strength  or  specific  gravity; 
therefore,  hydrometers  for  ascertaining  the  specific  gravity 


LEATHER  MANUFACTURE. 


c/Q-o 


of  liquids  lighter  than  water  are  constructed  for  the  use  of 
distillers,  manufacturing  chemists,  and  others. 

The  Barkometer. — To  enable  the  tanner  to  ascertain 
the  tanning  strength  of  his  liquors,  an  instrument  has 
been  devised,  called  a  barcometer  or  barkometer,  and  is  due 
to  the  ingenuity  of  Mr.  W.  Pike,  of  New  York.  It  is  thus 
described  by  Morfit : — 

"  It  is  made  wholly  of  glass  *  (see  Fig.  3),  a  d  being 
the  stem,  enclosing  a  graduated  paper  scale ;  B  is  a 
spherical  bulb,  and  C  a  smaller  bulb  at 
its  base,  containing  quicksilver  or  shot, 
which  serves  as  ballast  to  retain  the 
instrument  in  a  vertical  position  in  the 
liquid.  The  scale  on  the  stem  is  equally 
divided  into  five  or  ten  wide  spaces,  and 
each  of  these  again  subdivided  into  ten 
narrow  spaces.  The  zero  point  of  the 
scale  is  made  by  plunging  the  instru- 
ment into  distilled  water  at  58°  Fahr., 
and  adding  mercury  to  the  bulb  until 
it  sinks  to  nearly  the  top  of  the  stem 
at  a.  A  solution  of  ten  parts  of  bark  in 
ninety  parts  of  distilled  water  having 
been  made,  the  hydrometer  is  then 
plunged  into  the  liquor,  and  the  point 
to  which  it  sinks  therein,  say  b,  is 
carefully  and  accurately  marked  upon 
the  scale  and  rated  at  ten  as  compared 
with  the  zero  point.  Each  of  the 
grand  divisions  consequently  repre- 
Fig.  3.  sents  ten  per  cent,  of  bark,  and  each  of 

the  smaller  ones  or  subdivisions  corre- 
sponds with  one  per  cent,  of  the  bark.  It  is  very  easy, 
therefore,  after  having  determined  the  length  of  the  stem 
from  zero  which  sinks  in  a  normal  solution  of  bark,  to  ap- 
portion the  rest  of  it  with  the  aid  of  a  pair  of  dividers, 
so  that  every  interval  thus  apportioned  shall  be  equal  to 
that  fixed  by  experiment. 

*  Brass  barkometers  are  now  often  used  in  the  tanyard. — ED.  Fifth  Edition 


ESTIMATION  OF  TANNIN. 


"When,  therefore,  this  instrument  sinks  into  a  bark 
liquor  to  20°,  30°,  or  any  other  degree,  the  number  indi- 
cates the  percentage  of  tanning 
power.  [A  convenient  form  of 
hydrometer  glass  is  shown  in 
Fig.  4.]  It  is  necessary  to  ob- 
serve that  this  instrument  is 
applicable  only  to  freshly  made 
liquors,  for  otherwise  confusion 
and  want  of  confidence  might 
ensue  upon  finding  that  it 
sinks,  sometimes  to  a  corre- 
sponding degree,  in  spent  liquor. 
This  is  owing  to  the  fact  that 
the  alterations  which  tanning 
liquors  undergo  during  use  and 
exposure  may  not  diminish  their 
density,  though  they  impair  or 
destroy  their  tanning  power." 
Indeed,  the  accumulation  of 
gallic  acid,  vegetable  extractive, 
and  other  constituents  of  bark 
in  much-used  liquors,  would 
render  the  barkometer  practi- 
cally useless  as  an  indicator  of 
the  presence  of  tannic  acid.  It  should  therefore  only  be 
employed  in  testing  the  strength  of  fresh  liquors,  and  even 
then  the  liquors  should  always  be  tested  at  the  mean  tem- 
perature of  60°  Fahr.,  since  the  gravity  of  the  liquors  is 
greatly  influenced  by  their  temperature. 

Chemical  Methods  of  Estimating  Tannin. — The  earlier 
methods  of  determining  the  percentage  of  tannin  in  vege- 
table substances  were  based  upon  the  well-known  affinity 
of  this  substance  for  gelatine  ;  but  it  was  soon  discovered 
that  when  solutions  of  tannin  and  gelatine  were  mixed 
together,  the  first  precipitate  of  tanno-gelatine  contained 
a  larger  percentage  of  tannin  than  the  last,  and  conse- 
quently the  gelatine  test  was  open  to  objection  where 
absolute  accuracy  was  required.  This  method  of  forming 


Fig.  4. 


92  LEATHER  MANUFACTURE. 

an  approximate  estimate  of  the  percentage  of  tannin,  how- 
ever, is  useful  in  cases  where  the  higher  chemical  tests 
would  not  be  so  readily  understood. 

Davy's  Method.— One  ounce  of  dry  bark  is  reduced  to 
a  fine  powder  and  digested  in  a  pint  of  boiling  water,  with 
frequent  stirring.  After  twenty-four  hours'  repose,  the 
clear  liquor  is  filtered  through  a  cloth.  Now  dissolve  one 
drachm  of  the  best  isinglass  in  one  pint  of  warm  water 
with  stirring ;  add  the  isinglass  to  the  water  gradually, 
to  prevent  it  from  agglutinising.  Take  equal  quantities 
of  these  two  liquors  and  mix  them  together  ;  a  flaky  pre- 
cipitate is  at  once  formed.  The  mixture  must  now  be 
filtered  and  the  precipitate  collected,  dried,  and  weighed. 
The  difference  of  weight  indicates  the  proportion  of 
tannin.  The  precipitate  (tanno-gelatine)  generally  con- 
tains forty  per  cent,  of  tannin. 

In  examining  this  method  of  estimating  tannin,  Mr. 
Bortwick  found  that  much  of  the  precipitated  gelatine 
remained  in  the  filtered  liquor,  and  could  not  be  separated 
by  the  filter,  and  also  that  the  first  portions  of  the  preci- 
pitate contained  50  per  cent,  of  tannin,  while  the  latter 
portions  contained  very  little.  There  is  no  doubt,  how- 
ever, that  Davy's  estimate  was  based  upon  the  fact  that 
the  precipitate  was  a  compound  of  gelatine  and  tannin,  and 
if  the  weight  of  the  first  was  known,  the  difference  in 
weight,  after  careful  drying,  must  of  necessity  be  the  weight 
of  tannin  absorbed. 

Davy  also  suggested  the  following  method  :  A  piece  of 
skin  is  dried  and  weighed;  it  is  then  immersed  in  the 
liquor  containing  tannin  for  some  hours,  after  which  it  is 
dried  and  weighed  again.  The  increase  in  weight  gives 
the  quantity  of  tannic  acid. 

Bell  Stephens'  Method. — This  plan,  originally  sug- 
gested by  Davy,  is  based  upon  the  power  of  skin  to  absorb 
tannin.  A  piece  of  skin,  dried  over  a  hot- water  bath,  is 
carefully  weighed.  It  is  then  soaked  in  water  at  about 
90°  Fahr.,  until  perfectly  soft,  and  is  next  immersed  in  a 
weak  solution  of  the  tannin  to  be  examined,  which  should 
be  heated  to  about  90°  Fahr.  In  about  seven  or  eight 


ESTIMATION  OF  TANNIN.  93 

hours  the  skin  will  have  absorbed  all  the  tannin,  when  it 
is  again  dried  and  weighed.  The  increase  in  weight 
acquired  by  the  skin  indicates  the  quantity  of  tannin  it 
has  absorbed.  One  advantage  of  this  process  is  that  the 
appearance  of  the  skin,  after  being  thus  partially  tanned, 
shows  what  colour  the  tanning  material  would  impart  to 
leather  prepared  by  its  agency. 

Another  method  of  estimating  the  strength  of  tannins, 
upon  tho  above  principle,  is  to  take  a  given  weight  oi 
dried  shavings  of  unhaired  skin,  to  immerse  them  in  warm 
water  until  thoroughly  softened,  and  then  to  place  them 
in  a  weak  and  warm  infusion  of  the  tanning  material  to  be 
examined.  After  a  few  hours'  immersion  the  fragments 
of  skin  are  withdrawn  and  carefully  dried  over  a  water- 
bath  ;  when  perfectly  dry  they  are  again  weighed,  when 
the  difference  in  weight  will  show  the  amount  of  tannin 
which  has  been  absorbed.  Of  course  it  is  absolutely  neces- 
sary, in  adopting  these  methods  of  ascertaining  the  per- 
centage of  tannin,  to  leave  the  skin  sufficiently  long  in 
the  liquor  to  absorb  a II  the  tannin  ;  and  in  order  that  this 
should  be  determined  with  certainty,  a  few  drops  of  a  solu- 
tion of  gelatine  may  be  added  to  the  liquor  after  the  skin 
has  been  removed,  when,  if  no  turbidity  is  produced  by 
the  gelatine,  it  may  be  concluded  that  the  skin  has  taken 
up  all  the  tannin.  Again,  it  is  of  paramount  importance 
that  the  skin,  or  fragments  of  skin,  should  be  absolutely 
dry  at  the  time  of  weighing,  otherwise  all  calculations 
will  be  misleading. 

Hammer's  Method. — The  specific  gravity  of  the  tannin 
solution  to  be  tested  is  first  ascertained  by  means  of  the 
hydrometer  before  referred  to.  This  will  show  the  density 
of  the  solution  as  compared  with  water  (1000).  The 
tannin  is  next  removed  from  the  solution  by  immersing 
skin  in  it  until  all  the  tannin  has  become  absorbed.  The 
hydrometer  is  now  again  placed  in  the  liquor,  when  the 
decrease  in  its  density  or  specific  gravity  will  be  pro- 
portionate to  the  quantity  of  tannin  in  the  original 
solution. 

Besides  the  above  methods  of  estimating  tannin,  which 


94  LEATHER  MANUFACTURE. 

may  be  considered  to  give  fairly  approximate  rather  than 
actual  results,  there  have  been  many  processes  of  a  more 
purely  chemical  character  introduced  from  time  to  time, 
from  which  we  will  select  the  one  which  has  found  most 
general  acceptance  as  a  reliable  method  in  the  hands  of 
persons  accustomed  to  laboratory  manipulation.  We  refer 
to  the  process  of  Lowenthal,  which  has  been  the  subject 
of  much  consideration,  and  also  to  some  modifications  by 
which  it  has  been  rendered  somewhat  more  easy  of  ma- 
nipulation. 

LbwenthaVs  Method.— This  method  of  estimating  the 
percentage  of  tannin  is  generally  accepted  as  reliable, 
though  of  a  somewhat  complicated  character.  It  is  based 
upon  the  oxidising  power  of  permanganate  of  potash  ;  and 
this  system  of  analysis  by  oxidation  is  termed  titra- 
tion.  The  material  to  be  examined  being  mixed  with 
an  oxidi sable  substance,  as  indigo,  for  example,  is  titrated 
with  the  oxidising  agent,  which  in  Lowenthal's  pro- 
cess is  permanganate  of  potash.  The  process  is  thus 
described  :  *  — "  The  instruments  required,  besides  a 
good  balance  and  a  few  glass  beakers  and  funnels,  are 
merely  a  flask  gauged  at  the  neck  to  hold  a  litre,^  a 
few  pipettes  and  graduated  glasses,  and  a  Mohr's  burette 
with  a  glass  tap.  The  latter  is  simply  an  upright  tube 
with  a  tap  at  the  bottom,  graduated  down  the  side  like  a 
measuring- glass,  and  the  most  suitable  size  for  the  purpose 
is  one  delivering  twenty-five  cubic  centimetres,  and  divided 
into  two  hundred  and  fifty  parts. 

"  The  following  solutions  must  be  prepared  :  I.  Four 
grammes  of  pure  permanganate  of  potash  in  three  litres 
of  distilled  water.  II.  Five  grammes  of  pure  '  precipitated 
indigo  '  in  one  litre  of  water.  III.  Dilute  sulphuric  acid 
— one  part  acid  to  three  parts  water.  IV.  Twenty- five 
grammes  of  good  transparent  glue,  well  swollen  in  cold 
water,  and  then  dissolved  by  gentle  heat,  the  solution 
being  made  up  to  one  litre  with  water  and  saturated  with 
pure  table- salt.  Y.  A  saturated  solution  of  pure  salt  con- 

*  Tanners  and  Curriers'  Journal,  March,  1877. 
f  See  French  Tables  of  Weights  and  Measures. 


ESTIMATION  OF  TANNIN.  95 

taining  twenty-five  cubic  centimetres  of  sulphuric,  or  fifty 
cubic  centimetres  of  hydrochloric  acid  per  litre. 

"Although  this  seems  rather  a  formidable  list,  it  is  not 
a  costly  one,  and  all  the  solutions  may  be  kept  for  a  long 
time  in  stoppered  '  Winchester '  bottles.  To  make  an 
analysis,  10  grammes  of  sumach  or  20 '25  grammes  of  bark 
are  exhausted  by  boiling  with  water,  and  the  solution, 
when  cold,  made  up  to  one  litre.  Of  this  infusion,  10  cubic 
centimetres  are  mixed  with,  say  three-quarters  of  a  litre 
of  water,  25  cubic  centimetres  of  the  indigo  solution,  and 
10  cubic  centimetres  of  the  dilute  sulphuric  acid  are  added, 
and  then  the  permanganate  solution  is  run  in  drop  by  drop 
from  the  burette,  with  constant  stirring,  till  the  deep  blue 
of  the  indigo  changes  to  a  clear  yellow,  and  the  moment 
this  takes  place  we  note  the  quantity  of  permanganate 
used.  We  will  call  this  A.  Next  we  repeat  exactly  the 
same  process  with  the  indigo  and  eulphuric  acid  alone, 
and  we  will  call  this  quantity  B.  Then  subtracting  B 
from  A,  we  obtain  the  amount  of  permanganate  consumed 
by  the  total  astringent  of  10  cubic  centimetres  of  our 
tannin  infusion.  The  permanganate  acts,  of  course,  as  an 
oxidising  agent,  oxidising  and  consuming  both  the  tannin 
and  the  indigo;  but  as  the  tannin  is  the  most  readily 
oxidised  of  the  two,  it  is  consumed  first,  and  when  the 
indigo  is  all  bleached  [decoloured],  we  may  be  sure  that 
the  tannin  is  destroyed  also.  In  order,  however,  to  obtain 
this  satisfactorily,  the  proportion  of  indigo  should  be  such 
as  to  require  about  twice  the  quantity  of  permanganate 
which  should  be  consumed  by  the  tannin  alone.  Thus,  if 
the  indigo  alone  requires  10  cubic  centimetres  of  perman- 
ganate to  decolourise  it,  the  indigo  and  tannin  infusion 
together  must  not  take  more  than  about  25  cubic  centi- 
metres, and  if  it  does  so  the  tannin  infusion  must  be 
diluted  accordingly,  or  a  less  quantity  employed. 

"  The  next  step  is  to  ascertain  the  proportion  of  gallic 
acid  and  impurities  in  the  sample.  To  this  end  we  mix 
100  cubic  centimetres  with  50  cubic  centimetres  of  the 
salted  gelatine  solution,  and  then,  after  well  stirring,  add 
100  cubic  centimetres  of  the  salt  and  acid  solution,  and 


96  LEATHER  MANUFACTURE. 

leave  the  mixture  standing  for  some  hours,  or  all  night, 
and  then  filter  it  through  filtering-paper.  The  filtrate 
should  be  perfectly  clear.  If  we  now  test,  say  50  cubic 
centimetres  of  this  filtrate  with  permanganate  and  indigo, 
as  before,  we  shall  obtain  the  amount  of  permanganate 
required  for  the  gallic  acid  and  impurities  alone,  since  the 
tannin  has  been  entirely  precipitated,  and  the  gelatine  has 
so  trifling  an  action  on  the  permanganate  that  it  may  be 
safely  neglected.  To  make  the  working  clearer  we  will 
take  an  example  from  Mr.  Lowenthal's  paper : — 

Ten  grains  of  sumach  were  boiled  in  ^  litre  of  water,  and  after  cooling, 
were  made  up  to  1  litre. 

I'lO  c.c.  sumach  infusion  ) 

25  c.c.  indigo  solution     )  consumGd  16'6  c.c.  permanganate. 
The  same  repeated 16-5    ,,  „ 

33-1 
Indigo  alone 13'2 

Total  permanganate  for  20  c.c.  ) 
sumach    f  1; 

2-50  c.c.  filtrate  from  the  ) 

gelatine >  consumed  11 -2  c.c.  permanganate. 

25  c.c.  indigo  solution     ) 

The  same  repeated  11-1    ,,  „ 

22-3    „ 

50  c.c.  indigo  alone 13-2    ,, 

Gallic  acid  and  impurities 9-1    ,, 

"  Now,  deducting  9*1  cubic  centimetres  from  19'9  cubic 
centimetres,  we  have  10 '8  cubic  centimetres  as  the  per- 
manganate equivalent  to  the  tannin  of  20  cubic  centi- 
metres of  sumach  infusion,  or  0*2  gramme  of  dry  sumach. 
If  it  be  desired  to  compare  two  sumachs,  these  propor- 
tional numbers  are  all  that  is  necessary,  and  indeed  it 
will  be  quite  safe  to  use  them  for  comparing  sumach 
with  galls  or  pure  tannin.  In  the  same  way  bark  may 
be  compared  with  bark,  and  valonia  with  valonia,  but 
it  will  not  be  safe  to  attempt  by  this  means  to  com- 
pare bark  with  sumach  or  with  valonia,  because  the  dif- 


ESTIMATION  OF  TANNIN.  97 

fcrent  species  of  tannin  consume  different  proportions  of 
permanganate." 

Mr.  Hewitt  on  Lbwenthal's  Method. — With  a  view  to 
testing  the  accuracy  of  the  results  obtained  by  LowenthaPs 
method,  Mr.  F.  W.  Hewitt,  of  the  Royal  College  of  Che- 
mistry, made  a  series  of  experiments  with  different  tanning 
materials,  and  communicated  the  results  of  his  labours  to  the 
journal  referred  to,*  from  which  we  make  a  few  extracts. 
Mr.  Hewitt  observes: — "  1.  The  indigo-carmine  solution 
employed  must  be  quite  free  from  suspended  or  undissolved 
matter.  A  convenient  strength  to  use  is  such  that  20  cubic 
centimetres  thereof  shall  require  about  12  cubic  centimetres 
of  permanganate  solution  (1/5  gramme  of  the  salt  to  the 
litre).  750  cubic  centimetres  of  water  should  be  used  to 
dilute  this  quantity  of  indigo,  as  the  changes  of  colour 
from  the  blue  to  the  various  shades  of  green,  and  lastly 
yellow,  are  more  distinct  than  if  the  solution  be  more  con- 
centrated. A  moderate  amount  of  dilute  sulphuric  acid 
added  to  the  indigo  does  not  influence  the  reaction."  Mr. 
Hewitt  prefers,  instead  of  using  a  beaker  glass  for  the  titra- 
tion  of  the  permanganate  solution,  to  employ  a  large  flask, 
capable  of  holding  about  48  ozs.,  and  to  agitate  the  con- 
tents by  giving  them  a  rotary  motion  during  the  reaction, 
lie  further  observes,  that  if  the  permanganate  solution 
"be  run  from  the  burette  somewhat  quickly,  a  slightly 
different  reading  can  be  obtained  from  that  which  is 
obtained  when  it  is  slowly  introduced.  When  the  approxi- 
mate amount  of  permanganate  required  is  known,  one  cubic 
centimetre  may  be  run  in  at  a  time,  and  the  flask  shaken, 
as  before,  about  six  times  between  each  addition  of  per- 
manganate. In  this  manner  more  uniform  readings  are 
obtained."  Mr.  Hewitt  says,  that  in  precipitating  the 
tannin  by  gelatine,  LowenthaPs  dilute  acid  solution  "  must 
not  on  any  account  be  deviated  from,  as  a  more  concen- 
trated acid  (hydrochloric)  would  act  upon  the  permanga- 
nate and  liberate  chlorine." 

Mr.  Hewitt  states  that  one  objection  to  LowenthaPs 
method  is  that  the  gelatine  solution  requires  a  certain 

»  Tanners'  Journal,  April,  1877. 

a 


98  LEATHER  MANUFACTURE. 

amount  of  permanganate  in  the  presence  of  free  acid, 
This  he  observed  by  adding  a  little  permanganate  to  an 
acidulated  aqueous  solution  of  gelatine,  when  the  colour 
was  discharged.  "  If  the  same  tannin  infusion  be  used  in 
duplicate  analyses  with  the  same  gelatine,  I  obtained  very 
clear  results,  even  when  slightly  different  strengths  of 
indigo  were  employed.  Both  indigo  solutions,  though  of 
only  slightly  different  degrees  of  concentration,  should  be 
previously  titrated  with  permanganate  solution." 

Mr.  Hewitt  gives  the  following  result  of  his  analyses,  in 
conducting  which  he  employed  the  same  infusion  of  tannin 
and  the  same  gelatine  solution.  The  results  are  expressed 
in  accordance  with  L6  wen  thai' s  proposition — namely,  in 
percentage  of  oxidisable  matter : — 

I.  Sumach  Infusion. 

1.  2. 

Tannin    45-3     45-8 

Oxidisable  matter,  not  tannin 54*7     54-2 

II.  Galls  Infusion. 

Tannin    75-2     75-0 

Oxidisable  matter,  not  tannin  24-8     25-0 

III.  Oak-Bark  Infusion. 

Tannin    .     87*3     87'3 

Oxidisable  matter,  not  tannin 12-7     12*7 

In  pursuing  his  experiments  further,  Mr.  Hewitt  found 
that  the  tanning  material  under  examination  should  be 
boiled  several  times,  with  successive  small  portions  of 
water,  in  order  to  obtain  constant  results  in  the  deter- 
mination of  the  respective  amounts  of  oxidisable  matter 
present,  and  that  a  simple  infusion  in  hot  water  did  not 
afford  such  results.  He  also  urges  that  the  sample  to  be 
examined  should  be  intimately  mixed,  so  as  to  obtain  a  fair 
average  in  the  portion  to  be  examined.  "  In  reference  to 
the  salted  gelatine  solutions,"  says  Mr.  Hewitt,  "if  the 
gelatine  be  not  heated  for  a  sufficient  length  of  time  on 


ESTIMATION  OF  TANNIN.  99 

the  water-bath,  with  common  salt  solution,  it  assumes,  on 
cooling,  a  jelly-like  condition,  and  the  solution  from  the 
precipitate  whicli  is  formed  when  the  gelatine  solution  is 
added  to  the  tannin  infusion,  filters  neither  quickly  nor 
clearly.  This  can,  however,  be  entirely  obviated  by  using 
a  gelatin  solution  of  a  perfectly  fluid  consistency."  He 
also  says  that  he  has  not  found  any  advantage  in 
allowing  the  precipitate  to  stand  for  several  hours,  as 
recommended  by  Lowenthal,  to  obtain  a  perfectly  clear 
filtrate.  He  thinks  that  half  an  hour  is  sufficiently  long, 
whereby  the  operation  of  testing  tanning  materials  is  con- 
siderably  accelerated.  The  following  results  were  ob- 
tained by  Mr.  Hewitt  from  the  same  sample  of  sumac, 
intimately  mixed,  and  completely  extracted.  The  strength 
of  each  of  the  four  respective  infusions  being  about  «> 
grammes  to  the  litre. 

l.          2.  3.  4. 

Tannin 59-5        692        59-64        59-68 

Oxidisable  matter,  not  tannin      40-5        408         40-36        40-32 


100-         100-         100-  100- 

"It  will,  I  hope,  be  allowed,"  observes  Mr.  Hewitt  in 
conclusion,  "by  your  practical  readers,  that  a  method 
which  yields  such  results  under  the  conditions  which  I 
have  endeavoured  to  trace  may  well  be  called  a  useful 
method." 

The  above  results,  based  upon  a  careful  and  exhaustive 
series  of  experiments,  clearly  indicate  the  usefulness  of 
Lowenthal's  method  of  testing  tanning  materials,  espe- 
cially when  subject  to  the  modifications  which  Mr.  Hewitt 
has  so  ingeniously  introduced.  The  difficulty  which  some- 
times arises,  however,  of  separating  minute  particles  of 
tanno- gelatine,  which  obstinately  remain  suspended  in 
the  filtrate,  and  thereby  affect  the  accuracy  of  analyses  in 
some  degree,  has  frequently  been  a  source  of  trouble  in 
this  and  other  cases  in  which  gelatine  has  been  employed 
to  precipitate  tannin.  To  overcome  this,  Prof.  H.  li. 
Procter  hit  upon  the  happy  idea  of  mixing  kaolin  (china 
clay)  with  the  liquid  before  filtration,  the  effect  of  which, 


loo  LEATHER  MANUFACTURE. 

he  says,  "  was  instantaneous  and  complete.  A  perfectly 
clear  filtrate  was  obtained  without  any  of  the  tedious 
waiting  which  before  was  necessary,  and  it  was  not  only 
free  from,  tannin,  so  far  as  I  have  been  able  to  ascertain, 
but  also  nearly  so  from  gelatine,  so  that  it  only  gives  the 
faintest  cloudiness  with  tannin  solution."  Kaolin  is 
constantly  used  by  photographers  to  remove  the  brown 
colour  derived  from  the  action  of  nitrate  of  silver  upon 
albumenised  paper,  from  their  sensitising  solutions,  which 
it  does  effectually  and  instantaneously.  A  pinch  or  two 
of  kaolin  is  put  into  a  pint  of  discoloured  sensitising 
solution,  the  bottle  well  shaken,  and  the  solution  at  once 
filtered,  when  it  passes  through  the  filter  perfectly  bright 
and  colourless. 

Prof.  Procter  on  Iidwenthal's  Method.— Prof.  Procter* 
thus  describes  the  system  he  adopts  in  working  Lowen- 
thal's  method: — "I  employ  permanganate  of  the  strength 
of  1  gramme  per  litre,  and  solution  of  the  purest  indigo- 
carmine  of  5  grammes,  with  50  cubic  centimetres  of 
concentrated  sulphuric  acid  per  litre,  using  a  25-cubic 
centimetre  burette,  and  20  cubic  centimetres  of  indigo 
solution,  which  consumes  about  15  cubic  centimetres  of 
permanganate.  The  quantity  of  astringent  used  must  not 
require  more  than  the  remaining  contents  of  the  burette. 
The  titration  is  performed  in  a  white  basin,  as  recom- 
mended by  Kathreiner,  with  about  three-quarters  of  a  litre 
of  good  water,  which  it  is  best  to  measure  approximately,  so 
that  if  it  contains  any  impurity  which  affects  the  per- 
manganate it  should  be  constant,  and  thus  eliminated  with 
the  indigo.  The  titration  is  finished  when  the  pure  yellow 
liquid  shows  a  faint  pinkish  rim.  This  acid  reaction, 
which  is  of  extraordinary  delicacy,  is  due  to  Kathreiner, 
and  is  quite  different  to  the  pink  caused  by  excess  of 
permanganate,  being  an  effect  common  to  all  pure  yellow 
liquids.  I  do  not  find  it  needful  to  make  the  titration  so 
slowly  as  has  been  advised;  the  permanganate  may  be 
dropped  rapidly,  with  vigorous  stirring,  so  long  as  there 
is  large  excess  of  indigo,  but  as  soon  as  the  bottom  of 

*   Journal  of  the  Society  of  Chemical  Industry. 


ESTIMATION  OF  TANNIN.  lot 

the  basin  can  be  seen  through  the  solution  it  must  be 
added  very  cautiously  and  with  occasional  pauses,  to 
allow  time  for  its  complete  mixture  through  so  large  a 
mass  of  fluid. 

"I  make  my  infusion  of  such  a  strength  that  I  can 
employ  5  cubic  centimetres  of  the  original  liquid  for  each 
titration.  This  is  repeated  twice,  and  the  results  added 
together  and  denoted  a.  I  then  take  50  cubic  centimetres 
of  the  infusion,  and  add  28*6  cubic  centimetres  of  a  freshly 
made  solution  of  Nelson's  gelatine  of  2  grammes  to  100 
cubic  centimetres.  After  shaking,  the  mixture  is  satu- 
rated with  salt,  which  brings  the  volume  up  to  90  cubic 
centimetres,  and  10  cubic  centimetres  of  dilute  sulphuric 
acid  (containing  one  volume  of  concentrated  acid  in  ten) 
and  a  teaspoonful  of  pure  kaolin  are  added.  It  is  best  to 
do  this  in  a  flask  in  which  it  can  be  well  shaken,  after 
which  filtration  may  be  at  once  proceeded  with.  Ten  cubic 
centimetres  of  this  filtrate  (=5  cubic  centimetres  of  the 
original  infusion)  are  employed  for  a  second  pair  of  titra- 
tions,  which  are  added  as  before,  and  the  result  denoted  b. 
If,  further,  c  be  the  quantity  of  permanganate  required  to 
oxidise  10  cubic  centimetres  of  decinormal  oxalic  acid,  and 
10  grammes  of  substance  have  been  employed  to  one  litre 
of  infusion,  c  :  (a — b)  :  :  6*3  :  x,  where  x  is  the  percent- 
age of  tannin  expressed  in  terms  of  crystallised  oxalic  acid. 
For  the  present  1  invariably  calculate  my  results  in  this 
way,  since  we  do  not  actually  know  the  relation  of  any 
single  tannin  to  permanganate,  even  Neubauer's  number 
for  gallo-tannic  acid  being  probably  too  high,  and  Oser's 
for  quercitannic  acid  being  only  a  fair  approximation.  It 
happens,  moreover,  that  this  last  equivalent  (62'36)  does 
not  differ  from  that  of  oxalic  acid  (63)  more  than  the  ordi- 
nary limits  of  error  of  such  estimation,  and  the  substitution 
is  therefore  of  no  commercial  importance,  while  it  is 
surely  better  to  employ  a  standard  which  is  easily  and 
exactly  verified  than  one  which  is  certain  to  be  modified 
by  further  research,  and  so  to  run  the  risk  of  either  having 
our  results  made  useless  for  further  comparisons  or  of 
establishing  a  false  and  arbitrary  equivalent.  What  is 


102  LEATHER  MANUFACTURE. 

wanted  for  practical  purposes  is  not  the  absolute  weight 
of  tannin  in  the  various  materials,  but  only  a  means  for 
the  relative  comparison  of  two  samples  of  the  same  mate- 
rials, cross  comparisons  of  different  tannins  being  simply 
delusive." 

Ramspacker's  Method.  The  Tannometer. — The  fol- 
lowing is  Dr.  John  Watts's  description  of  Muntz  and 
llamspacker's  apparatus,  called  a  tannometer,  for  esti- 
mating tannic  acid,  by  which  the  actual  tanning  power  of 
any  tanning  material  may  be  determined — "  The  appa- 
ratus may  be  briefly  described  as  a  shallow  gun  metal 
drum  of  about  200  cubic  centimetres  capacity,  per- 
manently closed  at  one  end  by  an  india-rubber  plate,  and 
capable  of  being  closed  watertight  at  the  other  end  by  a 
piece  of  depilated  hide,  when  clamped  upon  a  stand  over 
which  the  skin  has  been  previously  stretched. 

"  The  drum  is  perforated  at  the  side  with  a  screw,  to 
admit  the  introduction  of  the  tanning  liquor,  and  is  fitted 
above  with  a  screw-piston  to  compress  the  india-rubber 
disc.  When  the  piston  is  lowered  the  liquor  is  forced 
through  the  skin,  while  the  latter  retains  the  whole  of  the 
tannic  acid.  The  density  of  the  liquor  is  taken  before  and 
after  the  operation  by  means  of  a  very  fine  hydrometer 
graduated  to  a  special  scale,  when  the  difference  expresses 
at  once  the  percentage  value  of  the  liquor  operated  upon. 
In  order  to  compare  the  results  of  this  tannometer  with 
Hammer's  table  of  percentages  of  tannin  in  solutions  of 
different  densities,  and  to  compare  both  with  the  results 
by  evaporation,  a  number  of  experiments  were  undertaken 
by  the  inventor.  The  percentages  only  indicate  the  value 
of  the  particular  sample  under  examination.  The  numbers 
in  the  first  column  were  obtained  by  taking  the  specific 
gravity  at  15°  C.  (59°  Fahr.)  before  and  after  removing  the 
tannin  and  obtaining  the  percentage  equivalent  from  Ham- 
mer's table.  The  third  column  was  found  by  evaporating 
25  cubic  centimetres  in  a  platinum  dish  before  and  after 
the  removal  of  the  tannin,  and  drying  the  residue  for  three 
or  four  hours  at  100°  C.  (212°  Fahr.). 


ESTIMATION  OF  TANNItf.  103 

By  Specific  By  By 

Gravity.  Tannometer.        Evaporation. 

Cube  Gambler 41-45     ....     40-44      ....     47-43 

Bale          „          42-24      30-50      ....      49-02 

Cutch..  47-70  44-60  o2-16 


Valonia 25-32 

Myrobalaus 32-30 

Mimosa  bark     31-44 

Blue  galls 60-60 

Green  „     53-40 

Sumac    17-10 

Dividivi    .  34-50 


25-32      26-30 

30-28  ....  31-08 

30-16  ....  31-72 

69-10  ....  — 

52-41  .  57-90 

18-00  ....  19-55 

33-94  35-20 


Casali's  Process. — This  is  founded  on  the  fact  that  a 
neutral  solution  of  sulphate  of  nickel,  containing  a  salt  of 
ammonium,  completely  precipitates  tannin  from  its  solu- 
tions, forming  flocks  which  easily  collect  together.  He 
prepares  his  standard  solution  as  follows  : — 2*89  grammes 
of  pure  sulphate  of  nickel,  previously  dried  at  518°  to  572° 
Fahr.,  are  dissolved  in  boiling  water  with  the  addition  of 
a  few  drops  of  sulphuric  acid,  and  100  cubic  centimetres 
of  a  30  per  cent,  solution  of  sulphate  of  ammonia  are 
added.  One-half  the  mixture  is  mixed,  drop  by  drop, 
with  ammonia,  until  it  assumes  a  violet-blue  colour.  The 
other  half  is  then  added,  and  the  whole  diluted  to  one 
litre.  The  solution  is  not  affected  by  glucose,  glycerine, 
tartar,  or  alkaline  oxalates  and  succinates.  One  c.c.  pre- 
cipitates O'Ol  gramme  of  the  tannin  of  galls,  or  0'01497 
gramme  of  the  tannin  of  oak  bark.  To  determine  the 
tannin,  the  sample  of  ware — 20  grammes,  if  it  be  supposed 
to  contain  6 — 10  per  cent.,  and  10  grammes  or  less  if  it 
contains  more — is  powdered  and  extracted  with  water  at 
168°  to  176°  Fahr.,  so  that  the  total  bulk  of  the  filtered 
solution  may  make  up  -jVth  litre.  Ten  c.c.  of  it  are  mixed 
with  five  c.c.  of  alcohol,  and  the  standard  solution  is 
allowed  to  flow  into  it,  drop  by  drop,  from  a  burette.  As 
an  indicator,  he  uses  slips  of  filter  paper  steeped  in  a  mixed 
solution  of  perchloride  of  iron  and  copperas.  From  time 
to  time  a  drop  is  placed  on  a  little  square  filter-paper,  and 
allowed  to  pass  through  this  upon  the  iron  paper.  The 
reaction  is  complete  when  a  drop  no  longer  blackens 
this  paper. 


io4  LEATHER  MANUFACTURE. 

Standard  Method.  International  Association  of 
Leather  Trades'  Chemists. — There  are  few  substances 
which  present  so  many  difficulties  in  the  way  of  their 
accurate  estimation  as  tannin.  Although  the  subject  of 
the  accurate  determination  of  the  amount  of  tannin  in 
any  given  substance  has  received  the  attention  of  chemists 
for  a  great  number  of  years,  it  must  be  confessed  that  no 
absolutely  reliable  method  has  yet  been  discovered. 

One  of  the  chief  difficulties  in  dealing  with  tannin  is 
its  high  molecular  constitution,  which  permits  of  its  being 
decomposed  very  readily,  forming  fresh  compounds  which 
introduce  further  complications  into  the  proper  estima- 
tion of  the  original  tannin.  One  of  the  earliest  methods 
of  estimating  tannin  was  to  precipitate  the  tannin  with 
a  standard  solution  of  gelatine ;  but  this  and  other 
methods  involving  the  use  of  gelatine  were  found  to  be 
only  approximate  in  their  results,  and  not  sufficiently 
reliable  for  employment  in  commercial  analyses.  It 
would  occupy  too  great  a  space  even  to  mention  the 
many  different  processes,  gravimetric  and  volumetric, 
which  have  been  tried,  without  success,  to  solve  this 
problem.  Some  methods  which  are  satisfactory  with  one 
particular  tannin  material  utterly  fail  when  dealing  with 
another  of  a  different  class.  It  is  obvious  that  some 
means  of  estimating  tannin  had  to  be  employed,  and,  in 
consequence,  chemists  adopted  methods  of  tannin  analyses 
which  their  own  fancy  dictated,  the  result  being  that 
great  discrepancies  in  the  percentage  of  tannin  in  the 
same  sample  occurred  when  analysed  by  two  different 
chemists. 

As  the  subject  of  tannin  analyses  grew  in  importance, 
it  became  imperative  that  a  standard  method  should  be 
devised  to  be  employed  in  all  tannin  estimations,  which 
would  at  least  procure  concordant  results,  if  not  accurate 
determinations  of  tannin.  With  a  view  to  establishing 
such  a  method,  a  conference  of  those  principally  interested 
was  called  in  London  in  1897,  the  result  of  which  con- 
ference was  the  formation  of  an  International  Association 
of  Leather  Trades'  Chemists,  who  agreed  to  adopt  one 


ESTIMATION  OF  TANNIN.  105 

"standard"  method  in  all  tannin  estimations.  The 
method  which  was  agreed  upon  is  known  as  the  "  hide- 
powder  filter  method ;"  but  at  the  annual  meeting  of  the 
association,  additions  to  and  alterations  in  the  originally 
adopted  method  are  constantly  being  made.  The  hide- 
powder  filter  method  consists  in  detanizing  the  tannin 
solution  by  means  of  hide  powder  placed  in  a  "bell 
form "  of  filter  through  which  it  is  syphoned.  The 
method  is  carried  out  as  follows :  First,  the  infusion 
of  the  tannin  material,  or  the  solution  of  extract  (the 
strength  of  these  depends  on  the  material  under  ex- 
amination, an  infusion  is  usually  made  with  between  20 
to  40  grms.  of  the  material,  according  to  its  richness  in 
tannin.  An  extract  solution  is  made  between  12  to  20  grms. 
of  extract.  In  both  cases  1  litre  of  the  liquor  is  made), 
is  filtered  through  what  is  known  as  the  "candle"  filter, 
which  is  used  largely  in  bacteriological  laboratories.  The 
vacuum  pump  is  used  to  facilitate  this  filtration,  the  object 
of  which  is  to  get  rid  of  all  insoluble  matter. 

It  is  usual  to  filter  only  about  half  of  the  litre,  the 
whole  having  been  previously  well  shaken.  50  c.c.  of 
the  clear  filtrate  is  taken  for  the  estimation  of  the  "  total 
soluble  "  matter.  This  is  done  by  evaporating  to  dry  ness 
in  a  weighed  porcelain  basin  on  a  water-bath,  and  the 
residue  is  afterwards  dried  in  an  air  oven  at  about  105°  C., 
then  cooled  in  a  desiccator  and  weighed.  A  vacuum  oven 
is  preferable  for  drying  the  residue,  as  it  lessens  the  ten- 
dency of  the  tannin  matters  to  oxidise,  thereby  gaining 
in  weight. 

The  "total  soluble"  residue  contains  both  tannin  and 
non-tannin  matters,  so  that  it  becomes  necessary  to 
separate  them  in  order  to  estimate  either  the  "  tannin  " 
or  the  "  non-tannin."  This  separation  is  carried  out  on 
a  fresh  portion  of  the  solution.  The  standard  method 
consists  in  absorbing  the  tannin  matters  present  in  the 
liquor  by  means  of  the  hide-powder  filter  already  referred 
to ;  and  regarding  the  filtrate  (which  has  become  de- 
colourised in  passing  through  the  hide  powder)  as  contain- 
ing non-tannin  matters,  a  measured  quantity  is  taken, 


io6  LEATHER  MANUFACTURE. 

usually  50  c.c.  The  first  30  c.c.  from  the  filter  is  rejected 
as  containing  soluble  matter  from  the  hide  powder,  and 
the  second  50  c.c.  is  evaporated  to  dryness  in  a  weighed 
porcelain  basin,  and  treated  exactly  as  in  the  case  of  the  esti- 
mation of  the  total  soluble  matters.  The  difference  in  the 
weight  between  the  total  soluble  residue  and  the  non- 
tannin  residue  represents  the  amount  of  tannin  in  50  c.c.  of 
the  original  tannin  solution,  and  by  a  simple  calculation 
the  percentage  of  tannin  matter  in  the  original  extract  or 
tannin  material  can  easily  be  determined.  The  water 
contained  in  a  tannin  extract  is  determined  by  drying 
a  weighed  quantity  of  the  extract  at  110°  G.,  and  weigh- 
ing and  drying  alternately  until  the  weight  is  found  to 
be  constant.  The  residue  from  the  moisture  determina- 
tion is  termed  the  "total  dry  matter."  The  difference 
in  the  weights  between  the 'total  dry  matter  and  the 
total  soluble  matter  represents  what  is  termed  "  insoluble 
at  15°  C." 

It  will  be  observed  from  the  foregoing  that  the  standard 
method  of  tannin  estimation  possesses  only  moderate 
claims  to  scientific  accuracy,  and  differences  in  manipula- 
tion affect  the  final  results.  For  instance,  the  particular 
manner  in  which  the  hide  powder  is  packed  in  the  bell 
filter  has  an  important  bearing  on  the  results. 

There  are  many  modifications  of  the  hide-powder  filter 
method,  such  as  the  American  "  shake  "  method,  which 
consists  in  treating  a  definite  volume  of  the  clear  tannin 
solution  with  a  weighed  quantity  of  hide  powder  in  a 
glass  tumbler,  and  the  mixture  is  well  shaken  at  frequent 
intervals  in  a  machine  constructed  for  the  purpose.  The 
mixture  is  afterwards  filtered  through  an  ordinary  funnel 
having  a  plug  of  cotton  wool  in  the  neck,  when  the  fil- 
trate is  found  to  be  completely  detanised.  In  other 
respects  the  process  is  the  same  as  that  already  described. 

The  most  unsatisfactory  feature  in  all  the  methods 
where  hide  powder  is  employed  is  the  difficulty  of  obtain- 
ing a  regular  supply  of  hide  powder  of  the  same  quality. 
Experiments  are  being  made  with  chrome  hide  powder 
prepared  from  chrome  tanned  hides,  and  the  results  are 


ESTIMATION  OP  TANNIN.  to? 

said  to  be  more  uniform  than   those  obtained  with  the 
ordinary  hide  powder. 

In  conclusion,  it  is  to  be  feared  that  the  chemistry  of 
the  tannins  is  not  yet  fully  understood,  and  when  more 
light  is  thrown  upon  their  chemical  constitution,  doubtless 
more  scientific  methods  of  analyses  will  be  devised. 


CHAPTER  IX. 
PRELIMINARY  OPERATIONS. 

Treatment  of  Green  or  Fresh  Hides. — Method  of  Salting  Hides. — Cleans- 
ing the  Kaw  Hides. — Dried  Hides. — Softening  Dried  Hides. — Brain's 
Process.— Dry  Salted  Hides.— Wet  Salted  Hides.— Schultz's  Views 
on  the  Treatment  of  Hides. 

Preliminary  Operations.— Since  the  condition  of  the  raw 
hides,  as  they  are  received  by  the  tanner,  influences  their 
preparatory  manipulation,  it  will  be  necessary  to  consider 
them  under  the  three  different  heads  which  indicate  their 
condition,  namely :  1.  Green,  or  Fresh  Hides ;  2.  Dried 
Hides  ;  3.  Dry  Salted  Hides  ;  4.  Wet  Salted  Hides.  The 
first  embraces  those  hides  which  are  furnished  by  the 
slaughter-houses  and  butchers,  and  the  latter  such  as  are 
imported  from  different  parts  of  the  world. 

Treatment  of  Green,  or  Fresh  Hides. — Those  hides 
which  have  been  recently  taken  from  the  slaughtered 
animal  require  but  little  labour  to  cleanse  from  the  ordi- 
nary "  muck "  which  commonly  adheres  to  them ;  since 
the  hides  are  sold  by  weight,  however,  it  has  sometimes 
been  the  practice  of  unfair  vendors  to  augment  their 
weight  by  purposely  saturating  them  with  such  filthy 
matter. 

It  occasionally  happens  that  the  green  hides  of  the 
slaughter-house  cannot  be  at  once  used  by  the  tanner,  in 
which  case,  especially  in  warm  weather,  the  hides  are 
salted,  so  as  to  check  putrefaction.  For  example,  if  the 
hides  are  required  to  remain  in  stock  for  a  week  before 
undergoing  the  preliminary  process  of  washing  and  liming, 
about  four  or  five  pounds  of  coarse  salt  are  spread  over 


PRELIMINARY  OPERATIONS.  IO9 

each  liide ;  but  if  they  have  to  be  kept  for  a  longer  period 
about  twice  that  quantity  of  salt  is  used.  Imported 
hides,  as  those  from  South  America,  are  treated  with 
a  still  greater  quantity  of  salt,  sometimes  as  much  as 
20  Ibs.  being  used  for  each  hide,  according  to  the  size 
and  the  season,  the  average  quantity  being  about  15  Ibs. 
per  hide. 

Method  of  Salting  Hides.— The  Continental  system  of 
salting  hides,  known  as  Delande's  method,  consists  in 
spreading  the  hides  open  upon  the  ground  and  sprinkling 
the  flesh  side  with  salt,  but  more  liberally  at  the  edges  and 
along  the  spinal  parts.  The  hides  are  then  folded  or 
doubled  lengthwise  down  the  centre ;  the  remaining  folds 
are  made  over  each  other,  commencing  with  the  shanks ; 
next  the  peak  of  the  belly  upon  the  back ;  afterwards  the 
head  upon  the  tail  part,  and  the  tail  part  upon  the  head, 
and  lastly  doubling  the  whole  with  a  final  fold,  and  forming 
a  square  [or  cushion]  of  about  two  feet.  This  being  done, 
they  are  piled  three  or  four  together,  and  left  until  the 
salt  has  dissolved  and  penetrated  their  tissue,  which  is 
generally  in  about  three  or  four  days.  Thus  prepared 
they  are  sent  to  market.  Skins  may  be  dried,  even  after 
having  been  salted,  by  stretching  them  upon  poles  with 
the  flesh  side  outwards,  and  exposing  them  to  dry  air  in  a 
shady  place.  Ten  pounds  of  salt  in  summer,  and  some- 
what less  in  winter,  are  requisite  for  each  skin  of  ordinary 
size. — Dussauce. 

Cleansing  the  Haw  Hides. — It  is  of  considerable  im- 
portance that  the  hides,  before  being  submitted  to  the 
several  operations  which  constitute  the  tanning  process, 
should  be  freed  from  all  adhering  foul  matter,  blood,  &c. ; 
in  short,  the  hide  should  be  clean.  This  is  effected  after 
the  horns  are  removed  by  first  steeping  them  in  water  for 
several  hours — from  one  to  twelve  hours,  according  to 
their  condition — and  afterwards  removing  all  the  filth  thus 
softened  or  loosened  by  washing  in  clean  water,  a  run- 
ning stream,  where  practical,  being  preferable.  When 
the  hides  are  more  than  ordinarily  dirty  they  must  be 
removed  from  the  soaking  bath  and  scraped  with  a  blunt 


IIO  LEATHER  MANUFACTURE. 

tool,  Fig.   5,   on  the  beam,  trampled  upon  in  water,  and 
finally  well  rinsed.    When  a  running  stream  is  available 
it  is  considered  a  good  plan  to  secure 
the  hides  to  a  rack,  and  this  being 
fixed  in  the  full  force  of  the  stream, 
Fl'g-  5-  the  friction  of  the  water  loosens  and 

dislodges  the  objectionable  matter,  whereby  there   is   a 
considerable  saving  of  labour. 

Dried  Hides. — It  will  be  readily  understood  that  skins 
which  have  been  deprived  of  their  natural  moisture  by  ex- 
posure to  the  air  or  the  heat  of  the  sun,  without  under- 
going any  further  treatment,  for  export  purposes,  merely 
require  to  have  the  moisture  they  had  lost  in  drying 
restored  to  them  to  bring  them  to  the  condition  of  green 
or  fresh  hides.  And  this  is  so  in  fact ;  but  in  order  to 
facilitate  the  absorption  of  moisture  by  the  indurated  or 
hardened  surfaces  of  the  hides  without  wasting  their  sub- 
stance, a  certain  amount  of  mechanical  treatment  is  neces- 
sary. If  the  skins  could  be  soaked  in  boiling  water  they 
would  very  soon  recover  their  normal  condition ;  but  as 
gelatine  is  soluble  in  hot  water,  the  skins,  by  such  treat- 
ment, would  not  only  lose  considerably  in  weight,  but  their 
porous  structure — so  important  to  the  free  absorption  of 
tannin — would  become  altered,  if  not  destroyed.  Dried 
skins,  therefore,  must  be  brought  to  a  pliant  state  by  cold 
soaking  in  the  first  instance,  and  by  subsequent  beating, 
rubbing,  and  soaking  to  render  them  supple. 

Softening  Dried  Hides.  —The  dried"  or  "  flint "  hides 
of  Buenos  Ayres,  River  Plate,  and  other  localities,  are  first 
thrown  into  cold  water,  in  which  they  are  soaked  from  ten 
to  fourteen  days,  according  to  their  thickness ;  but  after 
being  in  soak  for  several  days  they  are  subjected  to  mecha- 
nical treatment  by  being  forcibly  rubbed  or  "  broken  "  with 
the  blunt  tool  on  the  beam,  after  which  they  are  again 
soaked  and  then  subjected  to  a  process  of  beating,  which  in 
most  establishments  is  effected  by  a  machine  called  the 
fulling  stocks,  which,  by  repeated  blows  of  the  hammer  or 
toes  upon  the  partially  softened  skin,  alternated  by  further 
eoakings,  eventually  reduces  the  hides  to  nearly  the  con- 


PRELIMINARY  OPERATIONS.  in 

dition  of  fresh  hides.     An  illustration  of  such  a  machine, 
as  nuide  by  Huxham  and  Browns,  is  shown  in  Fig.  6. 


Fig.  6. 

Brain's  Process. — A  process  for  softening  dry  hides 
and  puring  skins  from  lime  has  been  introduced  by  Mr.  T. 
Brain,  which  appears  to  have  commanded  some  attention 
from  the  trade.  In  an  address  to  the  Scottish  tanners,  he 
said,  "  I  have  succeeded  in  making  a  compound  not  only 
inoffensive,  but  emitting  a  pleasant  odour,  which  I  shall 
be  prepared  to  sell  under  a  registered  title,  and  which  for 
dressing  leather  is  applicable  with  a  little  alteration  in 
the  use,  and  washing  through  clean  cold  water  afterwards, 

with  careful  scudding Tanning  of  dressed  leather 

prepared  by  my  process  does  not  require  the  liquor  to  be 
so  strong  or  new  at  commencement  as  skins  require  by 
the  bating  or  reducing  system  generally  in  use.  By  the 
old  way  the  pelts  have  parted  with  so  much  gelatine  that 
if  they  are  put  into  very  weak  liquor  they  go  on  losing 
gelatine.  But  by  using  a  moderately  strong  liquor  for 
a  day  or  two  it  closes  the  extremities  of  the  fibrine,  con- 
sequently the  gelatine  ceases  to  flow  out,  and  they  are  put 


H2  LEATHER  MANUFACTURE. 

into  a  weak  liquor  to  '  recover  breath.'  By  puring  the 
pelt  from  lime  and  not  reducing  by  bate,  it  retains  all  the 
gelatine,  and  should  be  well  handled  in  a  weak  stale  liquor 
for  a  day,  and  then  shifted  to  increased  strength  daily,  so 
that  a  gain  of  about  1  per  cent,  is  kept  up  additionally, 
commencing  at  about  6  degrees  for  dressing  and  10  de- 
grees for  sole." 

Dry  Salted  Hides,  as  those  from  Texas,  Pernambuco, 
&c.,  are  treated  much  in  the  same  way  as  dry  hides,  but 
are  somewhat  more  readily  softened  than  what  are  called 
"  flint  "hides. 

Wet  Salted  Hides  are  soaked  in  water  to  remove  the 
saline  matter,  after  which  they  are  rubbed  on  the  beam 
and  again  soaked,  until  they  are  in  the  proper  condition 
for  the  lime-pits. 

Schultz's  Views  on  the  Treatment  of  Hides.*— "  In 
all  the  processes,  commencing  with  the  soaking  and  mill- 
ing or  wheeling,  through  the  lime  or  bate,  each  pelt  must 
be  individually  treated  ;  and  if  the  conditions  are  much 
varied,  more  judgment  and  care  will  be  necessary  in  their 
treatment  as  a  whole  than  if  they  are  substantially  alike. 
In  the  latter  case  ordinary  intelligence  would  suffice  to 
perform  creditable  work.  This  degree  of  intelligence  is  all 
that  the  employer  has  a  right  to  expect,  and  hence  the 
importance  of  making  as  light  drafts  upon  the  brain  power 
of  his  men  as  possible,  by  making  the  labour  uniform  on 
each  piece  of  stock.  How  few  calf-skin  tanners  in  this 
country  [America]  think  it  important  to  classify  their 
skins !  Do  they  not  work  all  skins,  from  six  pounds  to 
twelve,  in  the  same  pack  ?  Whatever  is  classed  as  '  veaP  go 
together ;  the  first  selection  that  is  thought  of  is  when  the 
finishers  are  wanting  stock.  The  packs  are  then  assorted, 
and  the  tanned  skins  are  selected  out  and  sent  to  the  cur- 
rying shop,  while  the  heavy  ones  are  given  another  liquor. 
This  is  beginning  at  the  wrong  end :  the  selection  should 
have  taken  place  before  the  skins  entered  the  beam  house, 
when  the  advantages  of  classification  would  have  been 
secured  all  the  way  through  the  process. 

*  "  Leather  Manufacture."    By  Jackson  S.  Schultz. 


PRELIMINARY  OPERATIONS.  113 

"  In  a  well-regulated  calf  or  kip-skin  yard,  from  the 
time  the  skins  enter  the  tannery  they  are  mated  (for 
reasons  hereafter  stated),  and  continue  this  connection 
through  the  whole  after  tanning  process.  But  how  can 
dissimilar  sizes  and  substances  be  suitably  paired,  and  so 
placed,  grain  to  grain,  as  to  fully  cover  each  other  ?  What 
has  been  said  thus  far  goes  to  the  advantage  of  the  intrinsic 
quality  of  the  stock  ;  but  suppose  some  hides  or  skins  are 
damaged,  or  partially  so  ?  These  should  by  no  means  be 
allowed  to  contaminate  the  good.  They  are  the  sick  mem- 
bers, and  must  be  placed  in  hospital  under  observation. 
They  may  not  all  have  the  same  disease,  and  must  be 
placed  ia  different  *  wards '  or  apartments  for  special 
treatment.  When  one  thinks  of  the  indiscriminate  and 
forcing  processes  which  valuable  stock  receives  at  the 
hands  of  many  tanners,  the  inhumanity  of  the  treat- 
ment is  forced  on  one's  mind.  Sick  or  well,  strong  or 
weak,  large  or  small,  the  same  methods,  the  same  trying 
ordeal,  must  be  passed  by  all,  and  that  so  few  should  break 
and  fail  is  a  wonder. 

"It  remains  only  for  me  to  say  a  word  about  the  im- 
policy of  working  a  variety  of  hides  in  the  same  yard.  It 
is  not  to  be  denied  that  some  tanners  succeed  in  making 
good  stock  out  of  a  variety  of  hides  under  treatment  at  the 
same  time ;  but  this  is  the  exception,  and  should  not  be 
ventured  upon  by  the  average  tanner.  At  least  one  sea- 
son's or  one  year's  hides  should  be  of  one  kind,  or  as 
nearly  so  as  possible.  Buenos  Ayres,  Monte  Video,  and 
Rio  Grande  are  sufficiently  alike  to  be  classed  together. 
Central  America  and  Matamoras,  and  even  dry  Texas,  are 
possibly  similarly  conditioned.  California  and  Western 
may  be  well  treated  as  similar  hides,  requiring  light  treat- 
ment ;  but  there  cannot  be  safely  treated  dry  salted  and 
dry  flint  hides  in  the  same  beam  house ;  lime  and  sweat 
stock  cannot  go  through  together  without  danger,  or  cer- 
tainly with  the  hope  of  the  most  satisfactory  results.  The 
best  leather  is  made  by  tanners  who  work  a  uniform  de- 
scription of  hide.  This  is  the  usual  experience,  and  ia 


ii4  LEATHER  MANUFACTURE. 

These  observations,  emanating  as  they  do  from  one  of 
the  most  experienced  and  observant  of  American  tanners, 
deserve  the  fullest  consideration,  and  few,  we  should 
imagine,  will  question  their  wisdom.  Of  all  the  members 
of  the  trade  in  any  country,  Jackson  Schultz  will  ever  be 
held  in  esteem  for  his  generous  desire  to  promote  the  wel- 
fare of  his  trade  by  freely  and  ungrudgingly  making 
known  the  results  of  his  own  vast  personal  experience  for 
the  benefit  even  of  his  competitors — an  attribute  but  sel- 
dom, and  it  must  be  acknowledged  with  regret,  found  in 
those  who  follow  the  art  of  tanning  in  this  country. 
Indeed,  the  reticence,  "  closeness,"  or  so-called  "  conserva- 
tism "  of  the  tanning  trade  in  this  country  are,  we  think, 
to  be  deplored ;  for  were  the  followers  of  this  great  art  to 
assist  each  other  by  the  interchange  of  ideas,  and  by  making- 
known  such  modifications  of  processes  as  may  from  time 
to  time  have  proved  successful,  not  only  individuals,  but 
the  whole  fraternity,  as  well  as  the  general  public,  would 
be  the  gainers. 


CHAPTER  X. 
DEPILATION,  OR  UNJIAIRING  SKINS  AND  HIDES. 

Depilation  by  Lime. — Properties  of  Lime. — Storing  the  Lime. — Liming. — 
Single  Pit  Method.— Working  in  Rounds.— Continental  Method  of 
Liming. — Supposed  Disadvantages  of  the  Lime  Process. — Dr.  Davy 
on  the  Action  of  Lime  on  Animal  Matter. — Working  on  the  Beam. — 
Hounding  the  Pelts.— Depilation  by  Sweating.— Cold  Sweating.— De- 
pilation  by  Acids. — Depilation  by  Saccharine  Matter. — Depilation  by 
Caustic  Soda.— Depilation  by  Bisulphide  of  Calcium.— Depilation  by 
Charcoal. — Depilation  by  Sulphide  of  Sodium.— Palmer's  Process.— 
Beck's  Process. — The  Pullman-Payne  Process. 

Depilation  by  Lime.— The  removal  of  the  hair  from 
skins  and  hides,  called  dcpilation,  or  unhairing,  and  which 
may  also  be  termed  dehairing,  is  performed  by  several 
different  processes,  but  that  which  finds  most  favour  in 
this  country  is  that  known  as  the  lime  process.  When  a 
fresh  skin  is  allowed  to  remain  for  a  certain  length  of  time 
in  a  mixture  of  caustic  (that  is  fresh)  lime  and  water,  the 
cuticle  or  epidermis,  together  with  its  hair,  readily  sepa- 
rates from  the  cut  is  or  true  skin,  while  at  the  same  time 
the  fatty  and  fleshy  matters  of  the  under  portion  of  the 
skin  become  easily  separable  by  the  operations  of  the 
fleshing  knife.  During  the  soaking  in  the  lime-pits,  the 
fatty  matters  become  partially  converted  into  an  in- 
soluble lime  soap,  whereby  the  fleshy  portions  are  loosened 
and  may  be  readily  scraped  from  the  under  surface  of  the 
true  skin. 

Depilation  by  lime  is  the  oldest  method  known,  and 
although  it  possesses  certain  disadvantages,  it  is  still  more 
extensively  adopted  than  any  other  method  of  unhairing. 
The  lime  is  made  into  what  is  called  milk  of  lime,  by 


ii6  LEATHER    MANUFACTURE. 

mixing  recently  slaked  lime  with  water  in  varied  propor- 
tions, the  weakest  mixture  being  that  in  which  the  hides 
are  first  soaked,  and  in  which  they  are  allowed  to  remain 
for  one  or  two  days,  after  which   they  are  transferred 
to  another  pit  containing  a  stronger  lime  mixture,  and  so 
on,  through  successive  steeps  of  increasing  strength  until 
the  scarf  skin,  with  its  hair,  readily  yields  to  the  touch, 
which  is  generally  the  case  in  from  two  to  three  weeks, 
according  to  the  texture  and  condition  of  the  hides  and 
the  temperature  of  the  atmosphere.     As  in  all  other  tanning 
processes,  however,  there  is  a  great  diversity  of  opinion  ; 
whether  the  process  of  liming  should  be  conducted  slowly 
in  weak   liquors,   or    as   quickly   as   possible   in   strong 
liquors,  is  yet  an  open  question.     The  old  tanners  used 
to  employ  very  weak  liquors,  in  which  the  process  of  depi- 
lation  occupied  several — sometimes  many — months  for  its 
completion.   Now,  however,  we  have  been  taught  to  believe 
that  so  long  a  soaking  as  even  three  weeks  causes  a  loss  of 
gelatine  ;    some   tanners,  therefore,  prefer   using  strong 
liquors,  whereby  they  are  enabled  to  unhair  the  hides  even 
in  so  short  a  time  as  about  seven  days ;  and  indeed  from  the 
very  nature  of  the  operation — that  of  removing  the  cuticle 
and  hair  chiefly — this  method  of  depilation  would  appear 
not  only  the  most  scientific,  but  also  the  most  practical,  if 
conducted  with   great  care.      It   is  found  also  that   the 
pelts,  after  treatment  in  the  strong  limes,  are  swollen  to 
their  fullest  extent,  and  that,  after  tanning,  they  give 
greater  weight  than  those  which  have  been  treated  for  a 
longer  period  in  weaker  lime  liquors.     When  we  reflect 
that  the  loosening  of  the  epidermis  on  the  one  side  of 
the   skin  and  the  fleshy  matters  on  the  other   are  the 
objects  of  liming,  if  this  can  be  effected  in  such  a  way 
that  the  true  skin  is  not  subjected  to  any  action  of  the 
lime  it  will  undoubtedly  be  an  advantage,  since  the  rais- 
ing or  swelling  can  be  effected  by  less  objectionable  or 
more  suitable  materials  than  lime.     The  nearest  approach 
to  a  perfect  system  of  liming  would  appear  to  be  that 
which  is  quickest,  for  in  this  case  the  gelatine  of   the 
skin  is  less  liable  to  be  dissolved  than  when  subjected 


DEPILATION,    OR    UNH AIRING  SKINS  AND   HIDES.    117 

for  a  lengthened  period  in  weak  liquor.  It  almost  appears 
contrary  to  principle  to  steep  hides  in  spent  or  weak 
lime  at  all. 

Properties  of  Lime. — Before  giving  the  various  pro- 
portions of  lime  employed  by  different  manufacturers,  it 
may  be  well  to  consider  what  is  the  nature  of  lime  and  to 
what  extent  it  is  soluble  in  water.  "When  chalk  or  lime- 
stone (carbonate  of  lime)  are  calcined  at  a  high  tempera- 
ture, water  and  carbonic  acid  gas  are  expelled,  and  oxide 
of  calcium,  or  lime,  remains  behind.  If  this  lime  be  again 
exposed  to  the  air,  it  readily  attracts  carbonic  acid,  and 
again  becomes  converted  into  carbonate  of  lime,  and 
assumes  the  form  of  a  white  powder.  If  a  lump  of  fresh 
lime  be  sprinkled  with  water,  in  a  few  moments  a  hissing 
and  crackling  sound  is  heard,  the  lime  splits  up  in  all 
directions,  with  evolution  of  steam,  the  heat  engendered 
being  so  great  as  to  be  capable  of  igniting  wood.  The 
lime  absorbs  about  31*0  of  its  weight  of  water,  and  falls 
into  a  dry,  white  powder  called  hydrate  of  lime — a  chemical 
compound  of  oxide  of  calcium  (lime)  and  water.  It 
is  an  ascertained  but  remarkable  fact,  discovered  by 
Dalton,  that  lime  is  more  soluble  in  cold  than  in  hot 
water ;  that  is  to  say,  water  at  60°  Fahr.  dissolves  yj-y, 
while  at  the  temperature  of  212°  Fahr.  (the  boiling-point 
of  water)  it  only  takes  up  T^yiy.  Mr.  E,.  Phillips  ascer- 
tained that  water  near  the  freezing-point  took  up  about 
one- seventh  more  than  water  at  60°  Fahr.,  and  nearly 
double  that  of  boiling  water. 

The  solubility  of  lime  at  the  several  temperatures  is  as 
follows : — 

A  pint  of  water  at  32°  Fahr.  dissolves  13 '25  grains  of  lime. 
GO         „          „         11-6         „ 

»»  »          212         ,,          ,,          6-7        »         ,. 

From  this  it  will  be  seen  that  in  cold  weather  the 
strength  of  the  lime  liquors  (if  an  excess  of  undissolved 
lime  be  present  in  the  lime-pits)  will  be  greater  than  in 
hot  weather.  Since,  however,  chemical  action  is  always 
more  vigorous  in  warm  than  in  cold  temperatures,  the 


n8  LEATHER  MANUFACTURE. 

weaker  solutions  of  lime  would  be  fully  as  active  in  sum- 
mer as  the  stronger  liquors  in  cold  weather ;  doubtless 
the  colder  temperatures,  however,  would  be  less  injurious 
to  the  pelt. 

As  to  the  proportion  of  lime  which  should  be  employed 
for  fifty  hides,  there  seems  to  be  great  diversity  of  opinioi). 
While  some  manufacturers  use  from  2£  to  3  bushels  for 
each  pit,  others  have  been  known  to  employ  more  than 
twice  as  much.  About  2  Ibs.  of  lime  for  each  hide  is  con- 
sidered a  good  proportion. 

Storing  the  Lime. — Bearing  in  mind  that  lime  deterio- 
rates by  absorption  of  carbonic  acid  from  the  air,  it 
requires  to  be  protected  from  its  influence  as  much  as  pos- 
sible. The  lime  should  be  kept  in  a  dry  closed  shed,  away 
from  contact  with  timber:  and  in  order  to  protect  the 
bulk  from  the  air,  it  is  sometimes  the  practice  to  sprinkle 
the  pile  with  a  little  water,  to  slake  the  lime  on  the 
exterior  surface,  which  falls  to  a  powder  and  acts  as  a 
covering  to  the  rest  of  the  heap.  Another  method  of 
treating  the  lime  is  to  place  it  in  a  large  pit  and  to  slaken 
it  with  water,  and  then  to  cover  the  whole  with  a  small 
quantity  of  water,  finally  covering  up  the  pit  with  hurdles 
and  matting.  The  thick  paste  of  caustic  lime  thus  formed  is 
taken  out  by  shovelfuls  at  a  time  as  required,  and  the  pit 
again  closed.  In  this  way  lime  is  said  to  be  preserved  in 
a  caustic  state  for  a  considerable  time,  which  would  doubt- 
less be  the  case. 

Liming. — There  are  two  methods  in  practice  for  carrying 
out  the  process  of  liming,  namely,  1.  The  Single  Pit  Method; 
and,  2.  Working  in  Rounds.  In  the  former,  the  same  pack 
of  hides  is  treated  in  a  single  pit,  with  additions  of  fresh 
lime  from  time  to  time,  and  in  the  second  the  hides  are 
first  placed  in  a  weak  lime  or  old  lime  liquor,  and  suc- 
cessively steeped  in  stronger  liquors,  until  the  epidermis 
yields  to  the  touch. 

Single  Pit  Method.— The  complement  of  lime  and  water 
being  introduced  into  the  pit,  the  hides  are  immersed  one 
by  one,  care  being  taken  to  spread  them  out  as  flat  as 
possible,  until  the  entire  number  is  immersed.  After  three 


DEPILATION,    OR    UNH AIRING  SKINS  AND  HIDES.     119 

or  four  hours  they  are  handled  or  removed  from  the  pit, 
being  piled  one  over  another  in  a  heap,  after  which  they 
are  then  returned  to  the  pit  as  before ;  after  a  few  hours 
they  are  subjected  to  a  second  handling  on  the  first  day. 
The  handling  is  effected  by  means  of  blunt-pointed  hooks 
(Fig.  7).  On  the  second  day,  the  hides  are  again  drawn, 


Fig.  7. 

and  allowed  to  remain  in  a  heap  as  before  for  an  hour  or 
so,  during  which  time  the  lime  at  the  bottom  of  the  pit  is 
gently  stirred  or  plunged,  and  the  hides  are  again  placed 
in  the  pit.  They  are  subjected  to  this  treatment  during 
the  first  three  or  four  days,  by  which  time  they  will  have 
become  considerably  swollen.  They  are  now  again  drawn 
and  placed  in  a  heap  as  before,  and  a  fresh  quantity 
of  slaked  lime  is  added  and  stirred  up  with  the  lime 
already  in  the  pit ;  the  hides  are  again  immersed,  and 
the  handling  and  stirring  of  the  liquor  repeated  once  a 
day  until  the  expiration  of  about  twelve  or  fourteen  days 
from  the  commencement,  by  which  time  they  will  gene- 
rally be  in  a  condition  for  unhairing.  The  same  lime 
liquors,  with  additions  of  fresh  lime  periodically,  may 
be  used  several  times,  or  until  the  liquors  give  indications 
of  being  charged  with  ammonia,  when  the  pits  must  be 
cleaned  out. 

Working  in  Bounds. — This  method  is  much  adopted  by 
some  tanners,  and  consists  in  working  a  series  of  pits  con- 
taining lime  liquor  of  different  degrees  of  strength.  The 
green  or  fresh  hides  are  taken  from  the  water-pits  and 
immersed  in  the  old  or  spent  lime-pit,  being  handled  as 
before ;  and  from  this  pit  they  are  shifted  to  the  next  or 
stronger  lime,  and  so  on  until  they  have  passed  through 
the  whole  series  of  three  or  four  pits.  Each  of  these  pits 
being  strengthened  by  fresh  additions  of  lime,  the  last  pit 
becomes  the  first  in  the  next  round,  and  so  on  until  the 
liquors  become  surcharged  with  ammonia,  when  they  are 


J20  LEATHER  MANUFACTURE. 

cleaned  out  and  recharged  with  fresh  liquor.  When  this 
system  is  adopted  it  is  necessary  to  employ  pits  close  to 
each  other  to  save  unnecessary  labour. 

Continental  Method  of  Liming. — The  method  of  liming, 
as  practised  on  the  Continent,  is  thus  given  by  Dussauce : 
"  In  some  parts,  as  in  France  and  Belgium,  well-hound 
tubs  are  preferred.  The  number  of  these  varies  from  five 
to  twelve,  and  the  solution  is  then  so  arranged  that  there 
is  a  regular  increasing  gradation  of  density  from  the  first 
to  the  last,  even  where  the  greatest  number  is  taken  advan- 
tage of.  The  first  of  these,  usually  called  the  dead  vat, 
contains  very  little  caustic  lime,  and  this  is  the  one  to 
which  the  hides,  after  washing,  are  exposed  in  commencing 
the  operation.  Here  they  remain  from  one  to  three  days, 
according  to  circumstances,  and  during  this  period  they 
receive  a  handling  at  regular  intervals,  some  twice  and 

others  three  times  a  day Before  the  reintroduction, 

the  contents  of  the  vat  are  well  agitated,  with  a  view  to 
distribute  any  undissolved  quicklime  through  the  liquid, 
so  that  there  be  no  partial  or  undue  effect  exercised  on  the 
skins.  The  workmen  likewise  contrive  to  spread  out  the 
latter  in  the  vat  as  much  as  possible,  and  so  every  part  has 
the  same  exposure  to  the  lime.  In  the  dead  vat,  however, 
there  is  very  little  if  any  quicklime  undissolved.  After 
remaining  the  allotted  time  in  the  first  vat  they  are  trans- 
ferred to  the  second,  which  contains  a  stronger  liquid,  or 
more  lime,  and  left  in  this,  with  occasional  overhauling, 
for  a  few  days,  after  which  they  are  put  into  the  third, 
and  so  on,  tiil  the  hides  ultimately  arrive  at  the  last  vat, 
which  contains  the  fresh  lime.  In  operating  in  this  rota- 
tion, the  dead  vat  of  one  batch  of  hides  becomes  the  live 
one  of  the  next,  and  so  on  in  succession.  The  time  which 
skins  take  for  thorough  liming  varies  according  to  their 
weight  and  texture.  Thus  the  lighter  skins,  as  of  the 
sheep,  are  sufficiently  acted  upon  in  three  to  five  days,  but 
ox  hides,  kips,  and  calf-skins  require  two  to  three  weeks, 
according  to  the  season In  many  parts  of  the  Con- 
tinent, however,  the  operations  preparatory  and  conductive 


DEPILATION,    OR    UNHA1RTNG  SKINS  AND  HIDES.     121 

to  the  depilation  last  two  or  three  months,  but  in  these 
cases  the  skins  are  partly  swelled,  so  that,  for  this  special 
treatment,  they  do  not  require  so  much  attention  in  the 
succeeding  stages.  The  quantity  of  lime  which  is  used  by 
the  different  tanners  is  somewhat  various,  and  dependent 
upon  the  size  of  the  hides,  but  the  average  is  from  18  to 
24  gallons  of  freshly  burnt  fat  lime — 3  to  4  cubic  feet 
measure — for  100  hides  of  average  size/'  Sometimes  hides 
are  limed  by  suspending  them  from  poles  in  a  deep  lime- 
pit,  whereby  considerable  time  is  said  to  be  saved  and 
much  less  handling  required. 

Supposed  Disadvantages  of  the  Lime  Process. — While 
the  process  of  liming  hides  and  skins  possesses  the  advan- 
tages of  simplicity  and  economy,  on  the  other  hand,  in  the 
opinions  of  some  persons,  it  presents  many  important  dis- 
advantages, which  render  its  employment  objectionable. 
This  view  is  held  more  especially  on  the  Continent.  The 
action  of  the  lime  is  stated  to  cause  a  portion  of  the  mem- 
branous matter  of  the  skin — which,  were  it  not  removed, 
would  enter  into  the  substance  of  the  leather — to  be  dis- 
solved, whereby  a  certain  loss  is  sustained.  Again,  liming 
renders  the  surface  of  the  hide  unequal,  and  by  entering 
the  cellular  structure  of  the  skin,  retards  the  action  of  the 
tan  and  causes  it  to  act  ununiformly.  That  this  latter 
effect  is  produced  there  is  no  doubt  whatever,  but  as  to  the 
former,  the  researches  of  Dr.  John  Davy,*  conducted  at 
Malta  in  1829,  prove  that  lime  has  no  injurious  action 
upon  animal  tissues. 

Dr.  Davy  on  the  Action  of  Lime  on  Animal  Matter. 
"  It  is  commonly  asserted  and  believed  that  lime  exercises  a 
corroding,  destructive  influence  on  animal  matter  in  general, 
and  that  animal  bodies  exposed  to  its  action  rapidly  de- 
compose, and  disappear.  Accordingly,  it  has  been  almost 
invariably  recommended  to  add  this  earth  to  graves  in 
instances  in  which  rapid  decay  is  considered  desirable,  as 
on  the  occasion  of  the  crowding  of  grave- pits  with  dead 
bodies  during  the  prevalence  of  pestilential  diseases.  From 
*  The  Chemist,  vol.  i.  New  Series,  p.  227. 


122  LEATHER  MANUFACTURE. 

the  results  of  many  experiments  which  I  have  made  with 
lime  on  animal  substances,  I  have  been  compelled  to  come 
to  the  conclusion  that  this  opinion  is  not  well  founded  in 
fact ;  indeed,  that  it  is  altogether  erroneous.  The  experi- 
ments were  commenced  in  Malta  in  the  summer  of  1829, 
and  they  were  carried  on  during  the  following  year.  The 
method  observed  was  to  immerse  the  animal  matter  for 
trial  in  cream  of  lime,  or  rather  a  paste  of  lime,  contained 
in  a  wide-mouthed  bottle,  well  corked  and  covered  with 
cerate  cloth  to  exclude  ingress  of  atmospheric  air  and  to 
preserve  the  lime  in  its  caustic  state.  One  of  the  first 
experiments  tried  commenced  on  the  27th  of  August. 
Portions  of  various  textures  were  immersed,  as  mentioned 
above.  They  were  taken  from  a  subject  in  a  state  of 
incipient  putrefaction,  and  they  exhaled  a  fetid  smell.  On 
immersion  in  the  lime  and  water,  as  might  be  expected, 
they  gave  off  a  strong  ammoniacal  odour.  They  were 
lirst  examined  on  the  24th  of  September ;  they  were  then 
all  in  excellent  preservation,  swollen,  but  not  corroded 
nor  their  delicate  tissue  injured."  At.  the  expiration 
of  seven  months,  namely  in  the  May  following,  the 
animal  substances  were  again  examined,  and  were  found 
to  be  much  in  the  same  state  as  before,  "the  texture 
of  each  part  distinct,  and  the  part,  as  a  whole,  easily 
distinguishable."  After  being  left  undisturbed  for  nearly 
two  years  they  were  again  examined,  when  considerable 
change  had  taken  place;  the  cuticle  had  become  soft 
and  transparent,  and  many  other  parts  had  become  un- 
distinguishable. 

In  a  second  experiment,  "  commenced  in  the  beginning 
of  October,  portions  of  skin,  intestine,  cellular  tissue, 
muscle,  tendon,  &c.,  were  similarly  treated.  The  results 
were  examined  on  the  5th  of  May  following.  Then,  on 
opening  the  bottle,  an  ammoniacal,  but  not  putrid,  smell 
was  perceptible.  The  parts  were  found  well  preserved, 
excepting  the  fatty  matter  contained  in  the  cellular  tissue, 
which  had  become  opaque,  white,  and  friable,  from  com- 
bination with  the  alkaline  earth  and  conversion  into  soap. 
The  tendon  was  somewhat  distended  and  rendered  more 


DEPILATION,    OR    UNIf AIRING  SKINS  AND  HIDES.    123 

transparent,  but  not  gelatinised ;  and  so  also  the  cutis,  the 
last  being  deprived  of  its  cuticle  and  hair."  Dr.  Davy 
found  that  "  after  animal  substances  have  been  subjected 
to  the  action  of  lime,  they  ceased  to  be  putrescent ;  they 
resisted  putrefaction,  whether  placed  in  air  or  plunged  and 

kept  in  common  water A  portion  of  the  cutis 

similarly  treated,  placed  in  confined  air  in  a  bottle,  after  a 
whole  month  emitted  no  unpleasant  odour  and  appeared  to 
be  unchanged.  I  have  observed/'  continues  Dr.  Davy, 
"  that  the  cuticle,  nail,  and  perhaps  hair,  are  to  be  excluded 
from  the  list  of  animal  substances  not  materially  altered 
by  the  action  of  lime.  On  the  cuticle  its  action  is  power- 
ful, and,  I  apprehend,  in  consequence  of  a  chemical  com- 
bination between  them  being  formed." 

Dr.  Davy  finally  arrives  at  this  conclusion,  as  the  result 
of  a  great  number  of  experiments : — "  That  lime  docs  not 
exercise  a  destructive  corroding  power  on  animal  Distances 
generally,  nor  one  promoting  their  decomposition,  but  on 
the  contrary,  a  preservative  and  decidedly  antiseptic 
power,  arresting  putrefaction  even  when  commenced,  and 
retarding  decomposition." 

From  the  foregoing  observations,  based  upon  a  series  of 
experiments  conducted  with  great  care  during  a  period  of 
several  years,  it  would  appear  that  however  objectionable 
the  presence  of  lime  may  be  if  not  carefully  eliminated  by 
bating,  by  dilute  acids,  or  other  means,  it  has  no  injurious 
effect  upon  the  cutis  rcra,  or  true  skin,  which,  when  tanned, 
constitutes  leather.  Assuming  Dr.  Davy's  deductions  to 
be  correct,  the  hypothesis  that  the  liming  process,  fairly 
conducted,  reduces  the  weight  of  the  hides  by  acting  upon 
and  dissolving  a  portion  of  the  gelatinous  tissue  of  the 
pelt,  must  be  fallacious.  It  is  easy  to  understand  that  after 
several  weeks'  immersion  in  the  lime-pit  the  fatty  matters 
of  the  hide  enter  into  combination  with  the  lime,  forming 
a  lime  soap,  and  that  the  cuticle  and  even  the  hair  will 
yield  to  the  action  of  the  lime ;  but  from  Dr.  Davy's  obser- 
vations it  would  appear  that  the  true  skin,  or  pelt,  would 
undergo  no  change  whatever  in  the  milk  of  lime  mixture 
in  which  the  hides  are  by  custom  immersed.  The  same 


I24 


LEATHER  MANUFACTURE. 


cannot,  however,  be  said  in  respect  of  hides  which  are 
steeped  for  several  days  in  spent  or  very  weak  liquors, 
since  the  solvent  action  of  the  water  upon  the  gelatine  of 
the  hide  in  these  cases  would  be  to  a  great  extent  unre- 
stricted. 

Working  on  the  Beam. — "When  the  hides  have  remained 
sufficiently  long  in  the  lime-pits  they  are  examined,  and  if 
the  cuticle  readily  separates  when  plucked  by  the  fingers, 
they  are  taken  out  and  removed  to  the  learn  house,  where 
they  are  submitted  to  certain  mechanical  operations  by 
which  the  scarf  skin,  with  its  hair,  is  removed  from  the 
grain  side,  and  the  flesh  and  fatty  matter  dislodged  from 
the  flesh  side.  These  operations  are  termed  respectively 
unhairing  and  fleshing. 

Unhairing. — To  accomplish  this  operation  the  skin  is 
laid  upon  a  convex  wooden  or  iron 
support  called  the  learn  (Fig.  8), 
with  its  flesh  side  inwards,  and 
the  beam  man  then  takes  a  two- 


Fig.  9. 

handled  tool,  called  the  unhairing 
knife  (Fig.  9),  the  blade  of  which 
is  blunt,  and  curved  to  fit  the 
convex  surface  of  the  beam.  Fig.  10  illustrates  the 
mode  in  which  the  unhairing  is  performed.  The  hair 
is  removed  very  easily  by  pressing  the  knife  downward 
with  moderate  force,  when  the  grain  of  the  skin  becomes 
exposed.  The  operation  of  unhairing  a  hide  is  performed 
very  quickly,  one  man  being  capable  of  unhairing  many 
dozens  in  a  day. 

Fleshing. — After  the  hair  is  removed  the  hides  are  fleshed, 
an  operation  which  requires  to  be  performed  with  more 
care  and  skill  than  the  last  operation,  because  the  knife 
with  which  it  is  effected  has  a  sharp  edge,  and  the  action 
of  the  tool  is  to  cut  or  shave  of?  the  fleshy  matters, 
whereas  the  unhairing  knife,  having  a  blunt  edge,  merely 


DEPILATION,    OR    UNHAIRING  SKINS  AND  HIDES.     125 

scrapes  or  rubs  the  loosened  epidermis  from  the  grain  side 
of  the  corium  or  true  skin.     In  using  the  fleshing- knife 


Fig.  10. 

(Fig.  11)  the  workman  has  to  be  very  careful  not  to  cut 
away  any  portion  of  the  true  skin,  his  object  being  only 
to  remove  the  fat  and  flesh,  so 
as  to  leave  the  corium  fully 
exposed  for  the  after  process 
of  tanning.  Fig.  12  illustrates  Fig.  11. 

the     operation     of     fleshing. 

After  unhairing  and  fleshing,  the  pelts,  as  they  are  now 
called,  are  thoroughly  washed  and  once  more  scraped  with 
a  blunt  tool  to  remove  any  lime  or  other  matters  that  may 
still  attach  to  them.  This  operation  is  called  scudding.  The 
fleshings,  as  they  are  called,  are  collected  and  pressed  into 
cakes,  and  sold  to  the  glue-makers,  as  also  are  the  ears 
and  all  projecting  parts,  which  would  be  useless  when 
tanned.  The  hair  was  formerly  used  chiefly  by  plasterers 
for  mixing  with  mortar,  but  it  is  now,  after  being  thoroughly 


126 


LEATHER  MANUFACTURE. 


washed  and   cleansed,   employed  in   the  manufacture  of 
cheap  clothing,  blankets,  and  imitation  sealskin. 

It  is  not  always  the  case  that  the  fleshing  is  carried  out 
to  the  fullest  extent,  leaving  nothing  but  the  true  skin  to 
be  tanned.  Some  manufacturers  prefer  to  leave  a  portion 
of  the  flesh  attached,  so  that  the  butts  should  present  a 
more  mottled  appearance,  while  some  of  the  American 


Fig.  12. 

tanners  merely  have  the  flesh  side  lightly  scraped,  by 
which,  of  course,  greater  weight  is  given  to  the  leather. 
For  the  finest  quality  of  bark- tanned  butts,  however,  it  is 
essential  that  nothing  but  the  true  skin  should  enter  the 
tan  pit,  and  since  this,  being  quite  free  from  fleshy  matter, 
is  very  easily  injured,  great  care  is  necessary  in  the 
handling  of  the  pelts  in  the  earlier  stages  of  the  tanning 
process. 

Bounding  the  Pelts.— It  was  formerly  the  custom  to 
tan  the  hides  whole,  after  unhairing  and  fleshing,  but  the 
system  adopted  at  the  present  day  is  to  remove  with  a 
sharp  knife  all  the  inferior  parts  of  the  pelt,  and  to  tan 
the  butts  and  bends  separately.  To  this  end  the  hide  is 
taken  by  two  men  and  laid  upon  a  table  called  the  rounding 


DEPILATION,    OR    UNHATRING  SKINS  AND  HIDES.     127 


table,  it  is  then  doubled  from  end  to  end,  grain  side  out ; 
the  head  is  then  removed  by  a  cross  cut  with  the  rounding 
knife  (Fig.  13) ;  the  rough  edges  of 
the  tail  end  are  then  cut  away  or    tm^n, 
rounded,  and  the  sides  or  bellies  are 
next  cut  off,  either  by  one  cut  or  Fig.  13. 

separately.     By  this  method,    how- 
ever, the  rounder  is  unable  to  see  those  defects,  irregu- 
larities, or  brand-marks  which  may  be  on  the  under  side, 
and  consequently  cannot  trim  the  hide  in  such  a  way  as 
to  make  the  best  of  it.     It  is  considered  a  better  plan, 


Fig.  H. 

therefore,  to  lay  the  hide  across  a  wooden  frame,  or  horse, 
supported  by  trestles,  the  frame  of  which  forms  a  tri- 
angular arch.  The  hides  being  laid  across  this,  the 
rounder  is  able  to  see  all  parts  of  the  hide,  whereby  he 


128  LEATHER  MANUFACTURE. 

is  enabled  to  perform  the  operation  of  rounding  with  more 
skill  and  judgment.  The  accompanying  drawing  (Fig.  14} 
illustrates  by  the  dotted  lines  the  course  which  the  rounding 
knife  should  take  to  separate  the  various  parts  from  the 
butty  A,  or  chief  part,  of  the  hide.  B  represents  the  shoul- 
der, c  c  the  cheeks,  and  D  D  the  sides  or  belly  pieces.  On 
glancing  at  the  somewhat  irregular  form  of  the  expanded 
hide  it  will  be  evident  that  some  judgment  must  be  exer- 
cised in  removing  the  surrounding  parts — which  are  tech- 
nically called  offal— from  the  butt,  so  as  to  make  the  most 
of  the  latter  or  more  valuable  part  of  the  hide. 

After  unhairing  and  fleshing,  the  hides  sometimes  pre- 
sent inequalities  as  to  thickness,  and  in  order  to  render 
them  more  uniform,  or  of  an  average  thickness  through- 
out, the  following  plan  is  adopted,  but  more  especially  on 
the  Continent :  The  hides  are  rubbed  with  a  smoothing 
or  polishing  stone,  which  is  a  tool  made  of  sandstone 
interiorly  moulded  so  as  to  lie  parallel  upon  the  beam,  and 
is  fixed  to  a  piece  of  wood  furnished  with  two  handles. 
With  this  the  hide  is  rubbed  to  bring  the  parts  as  nearly 
as  possible  to  an  equal  thickness.  By  repeated  rubbings 
or  scrapings  in  this  way  with  the  stone,  alternated  by 
washings,  the  dirt,  fleshy  parts,  and  lime  are  removed  as 
far  as  possible  before  tanning. 

Depilation  by  Sweating. — By  this  method  the  cuticle 
and  fleshy  matters  are  loosened  from  the  corium  by  a  pro- 
cess of  putrefactive  fermentation,  or  slow  decomposition. 
Although  this  process  is  more  generally  adopted  on  the 
Continent  than  in  this  country,  it  is  employed  by  some 
English  tanners,  and  is  in  some  respects,  if  carefully  con- 
ducted, preferable  to  depilation  by  lime.  After  removing 
the  horns,  the  hides  are  piled  in  heaps  for  several  days, 
after  which  they  are  laid  across  poles  in  a  close  apartment 
called  a  smoke-house,  heated  somewhat  above  the  ordinary 
temperature  by  means  of  a  smouldering  fire  fed  with 
spent  tan,  which  produces  no  flame,  or  by  steam  heat. 
In  this  room  the  hides  undergo  a  slight  superficial  fer- 
mentation, by  which  the  cuticle,  with  its  attached  hair, 
becomes  softened.  In  France  one-half  of  the  hide  is 


DEPILATION,    OR    UN  HAIR  ING  SKINS  AND  HIDES.    129 

first  sprinkled  with  salt  and  the  other  half  lapped  over 
it,  to  prevent  the  putrefaction  from  injuring  the  tissue 
of  the  skin. 

In  Germany  the  hides  are  first  piled  in  a  heap  and  then 
covered  with  spent  tan ;  in  a  short  time  putrefaction  sets 
in,  but  unless  great  care  is  exercised  the  hides  are  liable  to 
be  injured.  Another  system  is  to  pile  the  hides  on  a  bed 
of  litter,  then  to  cover  them  with  litter,  and  allow  them 
to  remain  for  twenty-four  hours,  after  which  they  are 
turned  over  and  examined  from  time  to  time  to  ascertain 
if  they  are  fit  for  unhairing. 

Cold  Sweating. — In  some  parts  of  the  United  States 
a  system  of  cold  sweating  is  practised,  the  hides  being 
exposed  to  damp  air  in  a  close  apartment.  The  air  is 
kept  moist  by  a  spray  of  water,  and  it  is  said  that  in 
from,  six  to  twelve  days  the  hair  comes  off  easily.  It 
is  further  stated  that  by  this  method  no  putrefaction 
takes  place,  but  the  loosening  of  the  epidermis  is  due 
solely  to  the  softening  action  of  the  moisture.  It  is 
obvious,  however,  that  by  the  above  methods  the  fatty 
matters  are  not  in  any  degree  removed  (as  is  the  case  in 
the  liming  process  to  some  extent),  consequently  these 
must  be  dislodged  by  mechanical  means  on  the  beam. 
The  American  system  of  cold  sweating  is  more  fully  given 
in  another  chapter. 

Depilation  by  Acids.— It  has  long  been  known  that 
acid  liquors  have  the  power  of  acting  upon  the  roots  of 
the  hair  and  cuticle,  so  as  to  render  them  easily  detached 
from  the  true  skin.  In  some  tanneries  dilute  sulphuric  acid, 
pyroligneous  acid  (wood  vinegar),  fermented  barley,  rye,  or 
bran,  or  sour  milk  are  used,  the  latter  agent  being  adopted 
by  some  Parisian  tanners.  Rye- water  and  fermented  barley 
are  also  sometimes  employed  after  the  skins  have  been 
limed,  as  a  substitute  for  bating.  Earley  or  rye  meal  in  a 
state  of  fermentation  were  at  one  time  much  used  as  a 
steep  for  loosening  the  cuticle  and  hair,  the  active  agent 
being  the  acetic  acid  formed  during  the  decomposition  of 
the  vegetable  matter.  Sulphuric,  hydrochloric,  and  oxalic 
acids  have  each  in  turn  been  employed  to  loosen  the  cuticle 


130  LEATHER  MANUFACTURE. 

and  hair,  thereby  enabling  them  to  be  removed  from  the 
true  skin  by  the  process  of  scraping  or  working  on  the 
beam ;  but  tanners  maintain  that  by  their  employment  the 
skins  are  swelled  to  such  an  extent  as  to  injure  them 
materially. 

The  weak  vegetable  acids  are  not  excluded  from  practice, 
more  especially  in  France,  Belgium,  and  parts  of  Germany. 
Many  of  the  Paris  tanners  submit  the  hides,  after  they 
have  been  soaked  in  water,  washed,  and  fleshed,  to  a  number 
of  acid  vats,  in  a  way  analogous  to  the  liming.  Generally 
the  series  of  baths  consists  of  five,  which  from  the  first  to 
the  last  increase  in  power  and  efficacy.  The  first  is  usually 
intended  to  cleanse  the  hides,  the  second  to  soften  the  hair 
and  epidermis  for  the  depilation,  and  the  other  three  to 
swell  and  give  body  to  the  skins.  This  operation,  which 
is  called  the  white  dressing,  requires  a  period  of  five  weeks 
in  the  summer  and  six  in  the  winter  season.  The  quantity 
of  farinaceous  matter  which  is  taken  varies  at  different 
establishments — in  some  cases  145  Ibs.  of  barley-meal,  and 
in  others  150  or  160  Ibs.,  are  employed.  The  dressing  is 
generally  made  by  leavening  one-tenth  or  one-fifteenth  of 
the  bulk  till  it  becomes  sufficiently  sour ;  it  is  then  softened 
with  hot  water,  and  after  the  whole  has  become  a  thick, 
homogeneous  fluid  free  from  lumps,  it  is  added  to  the 
remaining  quantity  of  the  meal  in  the  vat,  and  tepid 
water  in  sufficient  quantity  is  poured  in  to  fill  the  vessel. 
In  some  cases  yeast  is  added  to  quicken  the  fermentation. 
Eight  or  nine  hides  are  worked  in  each  vat,  and  as  in 
the  lime  process,  the  weak  or  first  vat  passes  in  succession 
from  one  to  the  other  in  rotation.  The  final  vat  is  com- 
pounded of  60  Ibs.  of  meal  leavened  and  thinned  with 
water,  and  left  to  develop  acetic  acid  for  fifteen  days. 
In  all  of  these  operations,  handling  and  working  the 
hides  on  the  beam  at  regular  intervals  are  indispensable. 
— Dussauce. 

Depilation  by  Saccharine  Matter. — In  1844  Dr.  Turn- 
bull  obtained  a  patent  for  the  employment  of  sugar  as  a 
depilatory.  A  solution  is  prepared  by  dissolving  14  Ibs.  of 
coarse  sugar  in  100  gallons  of  water,  in  which  the  skins 


DEPILATION,    OR    UNHAIRING   SKINS  AND  HIDES.     131 

are  immersed  and  allowed  to  remain  for  eight  or  ten  days, 
being  handled  in  the  usual  way  daily.  As  soon  as  the 
hides  are  sufficiently  raised  they  are  removed  from  the 
sugar  steep  and  allowed  to  drain,  after  which  they  are 
immersed  in  a  strong  solution  of  sea  salt,  which  causes  the 
epidermis  to  contract  and  become  readily  detached  fiom 
the  true  skin.  After  washing  in  clean  water  the  hide  is 
ready  for  the  tan-pit.  It  does  not  appear  that  this  process 
has  received  much  attention,  but  there  is  much  in  its 
favour — more  especially  at  the  present  day,  when  sugar  is 
very  cheap — to  merit  reconsideration. 

Depilation  by  Caustic  Soda. — This  powerful  alkali  has 
sometimes  been  employed  for  unhairing  skins  and  cleansing 
the  flesh  side  from  fatty  and  fleshy  matters,  which  it  is 
capable  of  doing  with  great  rapidity,  but  extreme  caution 
must  be  exercised  in  its  employment.  In  order  to  ensure 
the  uniform  action  of  the  caustic  liquor  it  is  recommended 
either  to  suspend  the  hides  in  the  solution  or  to  continually 
handle  them  while  in  the  pit,  otherwise  the  thinner  parts 
of  the  skin  at  the  edges  will  be  acted  upon  by  the  caustic 
liquor  while  the  bulk  of  the  hide  may  be  but  little  affected. 
The  caustic  soda  is  prepared  by  adding  recently  slaked  lime 
to  a  boiling  solution  of  ordinary  soda  crystals  in  water, 
with  brisk  stirring.  After  a  few  hours'  repose  the  car- 
bonate of  lime  forms  deposits  at  the  bottom  of  the  vessel, 
when  the  clear  solution  of  caustic  soda  may  be  drawn  oft' 
for  use.*  The  solution  freely  enters  into  combination  with 
the  fatty  matters  of  the  hide,  converting  them  into  soap, 
which  may  be  recovered  from  the  bath  or  pit,  when  the 
liquor  has  lost  its  causticity  by  adding  sulphuric  acid  to 
the  liquor;  this,  combining  with  the  soda  of  the  soapy 
solution,  will  set  the  fatty  matters  free,  which  after  a 
while  will  rise  to  the  surface,  and  may  be  skimmed  off  and 
kept  in  casks  for  the  use  of  soapmakers.  Although  caustic 
soda  as  a  depilatory  has  not  been  much  used  in  England, 
it  is  very  questionable  whether  it  does  not  deserve  more 
consideration  than  has  hitherto  been  bestowed  upon  it. 

»  Caustic  soda  may  be  obtained  in  the  solid  state,  as  supplied  to  soap- 
makers,  &c.,  thereby  saving  the  trouble  of  preparing  it. 


132  LEATHER  MANUFACTURE. 

Depilation  by  Bisulphide  of  Calcium. — This  compound 
of  sulphur  and  lime,  commonly  called  sulphuret  of  lime,  in 
the  form  of  a  paste,  has  been  employed  as  a  depilatory  for 
skins  and  hides,  and  if  carefully  applied  is  very  effective 
ind  quick  in  its  action.  The  bisulphide  of  calcium  is  pre- 
pared either  by  passing  a  stream  of  sulphuretted  hydrogen 
gas  into  a  thick  milk  of  lime,  until  the  latter  is  super- 
saturated, or  by  taking  equal  parts  of  sulphur  and  quick- 
lime, and  after  slaking  the  lime  as  usual,  boiling  these 
substances  together  in  water.  The  paste  thus  obtained  is 
brushed  or  painted  carefully  over  the  hair  side  of  the  hide 
while  spread  upon  the  floor.  After  the  hides  have  been 
well  soaked,  a  light  coating  of  the  paste  is  given,  but  suffi- 
cient to  reach  the  surface  of  the  skin.  Since  the  sulphide 
would  readily  destroy  ordinary  brushes  or  swabs,  we  should 
think  that  brushes  might  be  made  with  asbestos — a  material 
which  would  not  be  so  readily,  if  at  all,  acted  upon  by  the 
caustic  sulphide.  As  the  skins  are  brushed  over  with  the 
sulphide  they  are  laid  one  above  another,  hair  to  hair, 
about  twenty  in  a  pile.  After  about  two  hours  the  position 
of  the  skins  is  reversed  by  lifting  the  uppermost  pair  and 
laying  them  by  the  side  of  the  pack,  and  upon  these  the 
other  pairs  are  placed  in  succession,  when  the  bottom  pair 
of  the  first  pack  becomes  the  top  pair  of  the  second  heap, 
by  which  a  more  uniform  action  of  the  sulphide  is  ensured. 
In  about  four  or  five  hours  from  the  commencement  the 
skins  are  in  a  condition  for  unhairing  on  the  beam  in  the 
ordinary  way ;  they  must,  however,  be  previously  soaked 
in  cold  or  tepid  water. 

It  is  stated  that  although  the  sulphide  is  so  powerful 
in  its  action  upon  the  cuticle  and  hair  (which  become 
practically  destroyed),  no  injurious  effect  is  produced  upon 
the  gelatine  of  the  pelt.  One  serious  objection  to  the 
employment  of  sulphides  in  the  above  operation  is  the 
highly  offensive  and  injurious  odour  which  these  sub- 
stances exhale,  and  which  cannot  be  long  endured  by  the 
workmen  with  impunity ;  indeed,  most  disastrous  effects 
are  known  to  have  resulted  from  their  employment. 

The  waste  lime  from  the   alkali  works,  which  is  bi- 


DEPILATION,   OR    UNH AIRING  SKINS  AND  HIDES.     133 

sulphide  of  calcium  in  a  concentrated  form,  and  also  the 
waste  lime  from  the  gasworks,  which  is  of  the  same  com- 
position in  a  less  active  state,  have  each  been  the  subject 
of  a  patent,  the  latter  being  stated  to  unhair  the  skins  in 
from  four  to  eight  days.  If  it  be  a  fact,  as  stated,  that 
the  bisulphide  of  calcium  has  no  effect  upon  the  gelatine 
of  which  the  true  skin,  or  pelt,  is  chiefly  composed,  this 
substance  should  prove  more  economical  than  the  ordinary 
process  of  liming,  by  which  a  considerable  loss  of  gelatine 
is  said  to  be  sustained,  although  this  is  disproved  by  Dr. 
Davy,  as  we  have  shown.  Since  the  bisulphide  of  calcium 
does  not  raise  the  pelt,  this  must  be  effected  by  after 
treatment  in  the  dilute  acid  bath  before  the  hides  are  sub- 
jected to  the  tanning  operation. 

Depilation  by  Charcoal. — This  process  was  patented  by 
Anderson  in  1871.  Wood  charcoal  was  applied  as  a 
substitute  for  lime,  and  in  much  the  same  way.  The  hair 
was  effectually  loosened,  but  the  process  was  simply  one 
of  putrefaction,  as  in  the  ordinary  "  sweating  "  processes, 
while  the  charcoal  acted  as  a  deodorising  agent. 

Depilation  by  Sulphide  of  Sodium. — For  sole  leather 
Eitner  recommends  the  following  method  of  applying  this 
powerful  depilatory : — Dissolve  4  or  5  Ibs.  of  the  sulphide 
in  each  gallon  of  water.  Form  this  into  a  thin  paste  with 
lime  or  pipeclay.  The  paste  is  to  be  spread  evenly  over  the 
hair  side  of  the  hide,  which  is  effected  by  one  workman 
pouring  it  from  a  pail  down  the  middle  of  the  hide,  while 
another,  with  a  mop  or  cane  broom,  rubs  it  into  every  part. 
The  hide  is  then  folded  into  a  cushion  and  set  aside.  In 
from  fifteen  to  twenty  hours  it  will  be  ready  for  unhairing, 
when  it  will  be  found  that  the  hair  is  reduced  to  a  pulp, 
and  therefore  totally  destroyed.  In  the  above  concen- 
trated condition  the  hair  would  doubtless  be  destroyed  in  less 
than  an  hour.  The  hides  are  now  thrown  into  cold  water, 
to  wash  away  the  sulphide  and  to  enable  them  to  plump. 
The  sulphide  being  highly  caustic,  it  will,  if  not  removed 
by  washing,  attack  the  nails  and  skin  of  the  workmen, 
who  should  be  thoroughly  cautioned  as  to  its  use,  other- 
wise they  will  soon  suffer  from  "  alkaline  sores  "  of  a  most 


134  LEATHER  MANUFACTURE. 

painful  character.  This  method  of  unhairing  gives  good 
weight,  as  also  tough  and  solid  leather,  but  it  requires  to 
be  used  with  very  great  care.  If  not  spread  evenly  upon 
the  hide,  patches  of  hair  may  remain  upon  the  pelt,  which 
will  be  troublesome  to  remove  afterwards.  Against  the 
advantages  derived  from  the  quickness  of  this  process 
must  be  placed  the  cost  of  the  material  and  the  loss  of 
the  hair.  Moreover,  unless  the  hides,  after  being  treated 
by  the  sulphide,  are  plumped  by  steeping  in  weak  lime, 
the  fleshy  matters  will  be  difficult  to  remove  on  the  beam. 
.Raising  by  acid  is  also  considered  necessary,  since  the 
sulphide  itself  has  but  little  plumping  effect. 

In  applying  this  process  to  dressing  hides,  the  sulphide 
is  used  in  a  more  diluted  condition,  the  hides  being  sus- 
pended in  a  solution  of  the  sulphide,  three-quarters  of  a 
pound  being  used  per  hide.  After  suspension  in  this 
solution  for  about  twenty-four  hours,  the  hides  are  in  the 
condition  for  unhairing,  after  which  they  are  limed  as 
before,  to  plump  or  swell  them. 

Palmer's  Process. — This  process  consists  essentially 
in  subjecting  hides  or  skins  alternately  to  the  action  of 
water  and  to  that  of  the  atmosphere.  After  the  hides  are 
cleansed  as  usual,  they  may  be  subjected  to  this  process 
by  placing  them  in  an  open  wheel  or  cage,  which  is 
caused  to  revolve,  with  its  lower  portion  immersed  in 
a  tank  containing  water,  whereby  the  hides  are  alter- 
nately plunged  in  that  liquid,  and  as  they  are  raised 
out  of  the  water  by  the  revolution  of  the  wheel,  the  air  has 
free  action  upon  them.  This  action  is  kept  up  until  the 
hair  or  wool  is  ready  to  remove.  After  unhairing,  the 
hides  or  skins  are  again  placed  in  the  revolving  wheel  or 
cage,  and  the  operation  continued  until  a  "  dark  colouring 
matter  can  be  made  to  exude  from  them  by  'scudding/ 
when  they  will  be  found  thoroughly  cleansed,  softened, 
swelled,  and  prepared  for  the  subsequent  tanning  or  taw- 
ing by  any  suitable  process."  The  process  is  further 
described  as  follows :  "  The  hides  or  skins  being  well 
soaked,  are  then  submitted  to  the  action  of  the  open  air 
for  about  three  days,  according  to  the  temperature  of  the 


DEPILATION,    OR    UNH AIRING  SKINS  AND  HIDES.     135 

atmosphere ;  but  in  no  case  must  it  be  long  enough  to 
generate  ammonia,  as  that  would  indicate  incipient  decom- 
position, and  therefore  destruction  of  gelatine.  The  hides 
are  then  returned  to  the  water  for  about  three  days,  after 
which  they  are  again  exposed  to  the  air,  and  so  on,  alternat- 
ing the  immersion  and  exposure  for  about  a  fortnight  from 
the  commencement  in.  the  case  of  wet  salted  hides,  when  they 
will  be  found  to  unhair  or  unwool  readily  ;  but  in  the  caso 
of  the  harder  and  drier  descriptions  of  hides  the  process 
will  require  to  be  continued,  say,  from  a  week  to  ten  days 
longer.  After  the  hides  are  unhaired  the  alternate  soak- 
ing and  exposure  to  the  air  is  again  repeated,  once  or 
twice,  until,  on  '  scudding/  the  hides  are  found  to  dis- 
charge a  dark  fluid,  which  I  term  *  suppressed  perspira- 
tion/ As  an  indication  of  the  time  when  the  hides  have 
arrived  at  the  stage  when  this  fluid  can  be  removed,  it  will 
be  found  that  they  give  off  a  very  disagreeable  effluvium 
(like  that  which  arises  from  an  over-driven  beast),  and 
different  from  the  ammoniacal  smell  usually  given  oil'  by 
hides  under  treatment.  After  the  complete  removal  of 
the  said  dark  fluid,  the  hides  will  be  found  to  be  fresh, 
pure,  soft,  and  sweet-smelling,  and  they  will  swell  in  the 
water  and  in  the  subsequent  liquors  to  a  better  and  higher 
degree  than  hides  treated  by  the  ordinary  and  more 
expensive  processes.  Such  swelling  of  the  hides  will  also 
indicate  the  perfect  removal  of  the  said  dark  fluid.  The 
atmospheric  temperature  which  I  find  best  suited  for 
carrying  out  my  process  is  about  65°  Fahr.  If  the  tem- 
perature be  higher,  less  time  will  be  required,  and  if  lower, 
more  time. 

"  The  hides  prepared  as  above  described  can  be  tanned 
in  a  considerably  shorter  time  than  when  prepared  by  the 
known  processes,  and  they  will  be  found  to  have  gained 
from  100  to  112  per  cent,  in  weight,  instead  of  only 
from  65  to  70  per  cent.,  as  is  the  case  under  the  ordinary 
processes  of  preparing  them  for  tanning.  As  a  pre- 
paratory treatment,  the  skins  or  hides  may  be  placed  in 
an  open  drum  or  cage,  which  is  caused  to  revolve  slowly 
with  its  lower  portion  immersed  in  a  receptacle  containing 


I3&  LEATHER  MANUFACTURE. 

water,  so  that  the  hides  are  alternately  immersed  in  the 
water  and  then  subjected  to  the  action  of  the  air,  but  this 
arrangement  need  not  necessarily  be  employed,  and  where 
it  cannot  be  conveniently  adopted  the  hides  may  be  at 
once  steeped  in  tanks  for  a  lengthened  time  and  then 
exposed  to  the  air  as  described." 

Beck's  Process. — In  carrying  out  this  process  the 
inventor  makes  a  "  water  stove  "  instead  of  a  fermenting 
stove,  but  with  this  difference,  that  instead  of  having  a 
hermetically  closed  chamber,  he  employs  an  open  vessel, 
as  a  pan  or  basin ;  he  arranges  hooks  exactly  as  in  the 
fermenting  stove,  and  upon  these  the  skins  are  suspended 
by  the  feet,  side  by  side,  care  being  taken  to  keep  them 
perpendicular.  The  skins  being  hung  up  and  descending 
nearly  to  the  bottom  of  the  pan,  the  latter  is  filled  up  with 
water  until  all  the  skins  are  submerged.  Into  this  "  water 
stove"  fresh  or  beaten  skins  may  be  placed.  "The  pro- 
longed stay  of  the  skins  in  the  water  naturally  causes  the 
peeling,  and  when  this  peeling  takes  place  the  skin  has 
not  suffered  at  all  in  the  water ;  on  the  contrary,  it  has 
gained  in  value,  and  the  wool  is  entirely  preserved. 
When  the  moment  for  peeling  has  arrived,  it  is  only 
necessary  to  empty  the  basin  or  pan ;  the  skins  are  drained 
separate!}',  and  they  can  be  peeled  easily.  By  this  water 
system  I  am  also  enabled,  while  preserving  the  skin  and 
the  wool,  to  accelerate  more  or  less  the  operation  of 
peeling.  It  is  preferable  to  let  the  skins  follow  their 
natural  course,  and  cold  water  may  be  used  both  in 
winter  and  summer.  It  will  be  understood  that  the  skins 
take  longer  to  peel  in  winter  than  in  summer,  but  no 
harm  is  occasioned  by  that.  If,  on  the  contrary,  it  is 
desired  to  accelerate  the  operation  of  peeling,  I  use  tepid 
or  hot  water,  and  I  add  to  the  bath  any  material  capable 
of  hastening  this  operation,  such  as  soap,  soda  crystals, 
strained  bran,  water,  &c.,  provided  always  that  the  mate- 
rials employed  are  not  such  as  would  injure  either  the 
skin  or  the  wool. 

"  I  may  observe  that  if  care  has  been  taken  to  put  the 
skins  into  the  water  stove  perfectly  scoured  and  washed 


DEPILATION,    OR    UNHAIRING  SKINS  AND  HIDES.      137 

(by  means  of  what  is  known  as  the  Ptiech  process,  for  ex- 
ample), wool  can  be  obtained  of  a  value  hitherto  unknown. 
By  my  process  of  peeling  the  leather  obtained  is  not  only 
worth  more,  but  it  can  be  manipulated  immediately  by 
the  tawer,  or  it  may  be  salted,  and  more  especially  it  may 
be  dried  without  losing  any  of  its  quality." 

The  Pullman-Payne  Process. — In  1898  Messrs.  Pull- 
man and  Mr.  S.  Payne,  of  Godalming,  patented  the 
method  of  liming  bearing  their  name,  and  which  appears 
to  have  been  used  with  a  certain  amount  of  success.  The 
method  depends  upon  the  fact  that  if  a  hide  which  has 
been  treated  with  caustic  soda  be  subsequently  treated 
with  a  solution  of  calcium  chloride,  a  double  decomposi- 
tion takes  place  and  lime  is  formed  in  the  fibre  of  the 
pelt,  the  sodium  uniting  with  the  chlorine  to  form 
common  salt.  In  practice  it  was  found  that  better 
results  were  obtained  if  the  hides  were  first  immersed  in 
a  putrefying  soak,  this  bearing  out  what  was  known  in 
liming  practice  that  there  was  some  joint  action  of 
bacteria  and  the  alkaline  solution  which  loosened  the 
hair  roots  in  the  process.  If  sodium  sulphide  is  added 
to  the  caustic  soda,  the  putrefactive  soak  is  not  necessary, 
but  the  hair  is  likely  to  be  damaged,  so  that  the  stale 
preliminary  soak  is  an  advantage.  The  patentees  recom- 
mend treating  the  hides  in  pits,  and  according  to  Procter 
the  caustic  soda  should  not  exceed  a  strength  of  one 
pound  in  ten  gallons  (1  per  cent).  The  hides,  or  calf- 
skins, remain  in  this  for  about  forty-eight  hours,  during 
which  they  are  once  drawn  and  returned,  by  which  time, 
if  the  putrid  soaking  has  been  properly  done,  the  hair 
should  be  fully  loosened.  The  hides  are  then  drained 
for  two  hours  and  passed  into  another  pit  containing  a 
solution  of  calcium  chloride,  which  should  be  slightly 
stronger  than  the  caustic  soda,  say  of  about  one  and  a 
half  pounds  per  ten  gallons.  The  goods  remain  in  this 
for  about  forty-eight  hours,  during  which  they  are  drawn 
once,  and  are  then  well  washed  in  soft  water  (free  from 
temporary  hardness),  in  which  they  may  be  kept  for  some 
time  without  injury. 


CHAPTER  XL 
RAISING  OB  SWELLING. 

Raising.— Bating. — The  Bate,  or  Grainer. — The  Pure. — Scudding. — 
Sulphuric  Acid  Bate. — Turnbull's  Process. — "VVarr in gton's  Process. — • 
Bating  with  Barley-meal. — Lactic  Acid  for  Bating. — Formic  Acid 
for  Bating. 

WHEN  the  hides  have  passed  through  all  the  foregoing 
operations,  the  pelts  are  soaked  for  a  few  hours,  sometimes 
for  many  hours,  in  water,  for  the  purpose  of  removing  the 
lime  as  far  as  possible.  The  more  lengthened  soaking, 
however,  would,  we  should  think,  be  not  only  absolutely 
unnecessary,  but  certainly  injurious,  inasmuch  as  the  water 
would  undoubtedly  dissolve  a  portion  of  the  gelatine  of  the 
hide,  and  thus  reduce  its  weight.  The  next  operation  to 
which  the  pelts  are  submitted  is  termed  raising  or  swelling, 
in  the  case  of  heavy  hides,  or  bating,  puring,  or  drenching, 
as  applied  to  kips  and  skins,  by  which  the  whole  or  a 
greater  portion  of  the  lime  is  removed  from  the  interior 
of  the  skin,*  the  pores  become  dilated  or  expanded,  and 
the  fibrous  structure  of  the  skin  is  thereby  rendered  more 
susceptible  of  the  action  of  the  tan  liquors. 

Raising. — For  this  purpose  Macbride,  in  the  year  1774, 
applied  very  dilute  sulphuric  acid  (oil  of  vitriol).  The 
hides  were  immersed  for  about  forty-eight  hours  in  an 
acid  solution  composed  of  sulphuric  acid  1  part  and  water 
1000  parts.  Since  this  acid,  however,  forms  an  insoluble 
salt  of  lime  (sulphate  of  lime)  when  coming  in  contact 
with  the  lime  absorbed  by  the  skin,  its  employment  for 
this  purpose  could  not,  from  a  chemical  point  of  view, 
commend  itself,  although  it  has  been  very  extensively 

*  The  presence  of  lime,  even  in  small  quantities,  not  only  produces  a 
harsh  leather,  but  it  also  prevents  the  free  action  of  the  tannin. 


RAISING  OR  SWELLING.  *39 

adopted.  On  the  Continent  hydrochloric  acid  has  been 
employed  for  this  purpose,  and  also  as  a  substitute  for 
bating,  to  which  we  shall  have  next  to  refer.  A  more 
rational  system  than  either  of  the  above  has  been  much 
adopted  in  France,  and  has  found  favour  in  this  country 
with  some  tanners  ;  this  consists  in  steeping  the  hides,  in 
the  first  stage,  in  spent  tan  liquors,  in  which  gallic  and 
other  vegetable  acids  have  been  developed  during  the 
process  of  tanning.  These  acids,  combining  with  the 
lime,  form  soluble  salts  of  the  earthy  matter,  which  readily 
become  removed  from  the  skin  by  the  spent  liquor  in 
which  they  are  immersed.  In  this  way  the  lime  is  effec- 
tively, if  slowly,  got  rid  of,  while  the  texture  of  the  skin 
suffers  no  injury.  In  France  sulphuric  acid  is  believed  to 
have  an  injurious  effect  upon  the  pelt. 

Bating. — This  remarkable  and  primitive  process  is 
generally  confined  to  the  treatment  of  kip  hides,  calves' 
and  seal  skins,  by  the  light  leather  tanner,  and  to  the 
skins  of  goats  and  other  small  animals  by  the  skinner.  It 
has  for  its  object  the  removal  of  the  lime,  whereby  the 
skin  acquires  the  peculiar  suppleness  and  pliancy  essential 
to  leather  of  delicate  texture. 

The  Bate,  or  Grainer,  is  essentially  a  lixivium  com- 
posed of  the  dung  of  pigeons  and  fowls  in  water.  In 
this  unsavoury  mixture  the  unhaired  and  fleshed  skins  are 
immersed  for  a  period  of  ten  or  twelve  days,  or  for  a  shorter 
period  in  warm  weather.  By  this  process  of  bating,  with 
alternate  scraping  or  working,  as  it  is  termed,  the  lime  is 
believed  to  be  converted  into  a  soluble  compound,  and  thus 
becomes  separated  from  the  tissue  of  the  skin,  the  mechani- 
cal treatment  doubtless  aiding  the  operation  considerably. 
Dussauce  says:  "Investigation  has  shown  that  the  above 
matters  contain  an  ammoniacal  chloride  that  parts  with  its 
chlorine  on  coming  in  contact  with  the  lime,  and  so  gives 
rise  to  a  soluble  combination  of  this  base — chloride  of 
calcium— that  may  readily  be  abstracted  by  water.  But  if 
this  is  the  only  result  of  the  noxious  process,  dilute  hydro- 
chloric acid  should  answer  the  same  purpose.  That  this 
disgusting  method  should  still  continue  to  be  extensively 


I4o  LEATHER  MANUFACTURE. 

practised  is  disgraceful  to  modern  science.  It  is  stated 
that  in  London  alone  £5,000  used  annually  to  be  ex- 
pended in  collecting  and  purchasing  the  above  materials 
for  the  sole  use  of  the  tanners  of  the  capital  and  its 
suburbs.  Although  this  method  of  bating  hides  is  toler- 
ably effective,  yet  it  is  well  known  to  be  attended  with 
serious  disadvantages,  not  the  least  of  which  is  the  putre- 
faction of  the  bate  that  is  going  on  during  the  steeping, 
and  which  injures  the  hides  by  acting  upon  the  tissue  of 
the  skin,  reducing  its  weight  in  the  first  instance,  and  in 
the  second  rendering  it  incapable  of  yielding  the  quantity 
of  leather  it  should  doubtless  produce  did  the  above 
changes  not  occur.  Taking  the  hint  from  the  action  of 
the  alkaline  chloride  in  this  case,  some  tanners  have 
attempted  to  prevent  the  putrefaction  induced  by  the 
bating  with  excrements  by  avoiding  its  use  altogether, 
using  hydrochloric  acid  in  a  diluted  state  as  a  substitute. 
The  innovation  has  not  yet  become  very  general  in 
England,  although  many  tanners,  especially  in  Paris, 
are  reported  to  have  practised  it  successfully,  the  object  of 
the  expulsion  of  the  lime  being  satisfactorily  gained  by  it, 
and  in  addition  to  this  the  swelling  of  the  hides  also." 

The  Pure,  which  is  applied  to  the  skins  of  the 
lighter  kinds  of  calf,  goat,  seal,  sheep,  &c.,  is  prepared 
from  the  excrement  of  dogs,  but,  unlike  the  bate  or 
grainer,  which  is  prepared  with  cold  water,  the  pure 
employed  by  the  light  leather  dressers  is  employed  warm  ; 
indeed,  as  hot  as  the  skin  can  bear  without  scalding,  as  it 
is  termed.  But  it  is  an  ascertained  fact  that  the  skin  of 
the  dead  animal  can  bear  no  more  heat  than  the  hand  of  a 
living  human  being,  without  suffering  irreparable  destruc- 
tion. While  immersed  in  the  pure,  the  skins  are  re- 
peatedly moved  about,  and  the  pureman  has  to  exert  the 
utmost  caution  to  prevent  the  decomposition  which  ensues 
from  injuring  the  skins.  The  action  of  the  pure  is  not 
only  rapid  but  powerful,  especially  in  summer  weather. 

Scudding. — The  workman  forcibly  scrapes  the  skin  on 
the  beam,  which  operation  is  called  scudding,  by  which 
he  removes  the  decomposing  agent  and  the  salt  of  lime 


RAISING   OR   SWELLING.  141 

(chloride  of  calcium)  formed  during  the  immersion  in  the 
pure ;  and  in  order  to  prevent  further  decomposition, 
the  pelts  are  thrown  into  clean  cold  water.  The 
bating  and  puring  operations — especially  the  latter — are 
considered  the  most  critical  of  all  the  operations  of  the 
tanner  or  leather-dresser.  The  pure,  being  employed 
warm,  accomplishes  in  a  few  hours  that  which  the  bate 
requires  days  to  effect.  The  applications  of  the  bate  and 
pure  will  be  further  considered  when  treating  of  light 
leathers  and  skin-dressing. 

Sulphuric  Acid  Bate. — Sulphuric  acid  has  also  been 
suggested  as  a  substitute  for  the  bate,  but  while  its  action 
is  not  so  marked  as  when  hydrochloric  acid  (muriatic 
acid)  is  used,  it  must  also  be  remembered,  as  we  have 
before  observed,  that  sulphuric  acid  forms  an  insoluble 
compound  with  the  lime,  which  no  scraping  or  working 
can  entirely  remove.  This  acid,  however,  in  spite  of  this 
well-known  fact,  is  generally  used  for  raising  or  swelling 
heavy  hides  after  liming,  and  before  they  are  placed  in 
the  handlers  in  weak  solutions  of  tan. 

Turnbull's  Process.— Dr.  Turnbull  introduced  the  em- 
ployment of  saccharine  liquids  for  the  removal  of  the  last 
traces  of  lime  from  skins  as  a  substitute  for  the  bate.  For 
this  purpose  4  or  5  pounds  of  coarse  sugar  or  molasses, 
dissolved  in  60  or  70  gallons  of  water,  formed  the  bate. 
In  this  process  the  sugar  forms  a  soluble  saccharate  of  lime, 
which  subsequent  soaking  and  rinsing  removes. 

Warring-ton's  Process. — In  1841  Robert  Warrington 
patented  a  process  in  which  carbonate  of  ammonia  was 
employed  as  a  substitute  for  the  ordinary  bate  for  grain- 
ing skins.  The  carbonate  of  ammonia,  however,  although 
it  converts  the  lime  into  a  neutral  compound,  does  not 
eliminate  the  earthy  matter  from  the  hide  or  skin ;  conse- 
quently it  fails  to  promote  the  necessary  suppleness  and 
softness  of  the  skin,  which  are  the  chief  objects  of  the 
bating  process. 

Bating  with  Barley-meal. — As  a  substitute  for  the 
excrement  bate,  barley-meal,  made  into  a  sour  liquor,  is 
much  used.  For  100  Ibs.  of  dry  skins,  50  Ibs.  of  coarsely- 


I42  LEATHER  MANUFACTURE. 

ground  barley-meal  and  5  or  6  Ibs.  of  soured  dough  are 
taken  and  intimately  mixed  with  water.  Acetic  fermenta- 
tion soon  follows,  and  the  acid  generated  forms  a  soluble 
salt  with  the  lime  in  the  skins,  which  becomes  removed 
by  subsequent  washings. 

Lactic  Acid  for  Bating. — Of  late  years  lactic  acid  has 
come  into  favour  with  the  more  progressive  tanners  for 
bating  or  drenching.  Its  use  is  more  desirable  when 
fancy  shades  are  required,  as  it  is  stated  the  skins  come 
out  much  cleaner  and  clearer  than  by  the  old  methods. 
This  is  of  much  importance,  as  only  the  clearest  skins 
can  be  coloured  fancy  shades,  and  the  fancy  shades  bring 
a  much  higher  price  than  the  black  leather.  The  usual 
process  for  chrome-tanned  calf  skins  is  to  use  about  half 
a  gallon  of  50  per  cent,  lactic  acid  to  100  gallons  of 
water,  or  if  the  skins  are  lightly  limed  a  little  less  lactic 
acid  may  be  used.  The  skins  are  bated  in  a  paddle,  and 
water  of  about  85°-90°  Fahr.  is  used,  that  is,  the  water 
is  85°-90°  Fahr.  after  the  skins  are  in.  Before  they  are 
put  in,  the  water  should  be  at  least  10°  warmer. 

For  sheep  skins,  a  little  less  lactic  acid  is  used  than 
for  calf  skins,  and  if  plump  leather  is  desired,  the  water 
is  somewhat  cooler,  about  70°  Fahr.  For  goat  skins,  a 
"  pure  "  is  first  used,  and  then  the  skins  are  bated  in  a 
solution  of  1  gallon  of  lactic  acid  to  400  gallons  of  water, 
and  at  nearly  100°  Fahr. 

Formic  Acid  for  Bating. — Formic  acid  is  now  used 
for  de-liming,  and  also  as  a  preserving  agent  for  sheep 
pelts.  An  American  plan  is,  after  unhairing,  to  wash  in 
a  weak  solution  of  acid,  using  two  and  a  half  pints  of 
40  per  cent,  acid  to  ten  hides.  After  fleshing  and  wash- 
ing, the  pack  of  hides  is  then  washed  in  a  solution  of 
five  pints  of  formic  acid  in  135  gallons  of  water,  or  five 
pints  to  1120  Ibs.  of  pelt.  The  hides  are  washed  until 
de-limed,  that  is,  when  a  cut  section  remains  white  when 
touched  with  a  drop  of  phenol-phtalein.  If  the  section 
shows  a  reddish  reaction  the  bating  must  be  continued. 
Formic  acid  is  also  used  as  a  plumping  agent,  and  for 
developing  "  acid  "  colours  in  leather  dyeing. 


CHAPTER  XII. 
TANNING  BUTTS  FOR  SOLE  LEATHER. 

Bark  Tanning. — Old  Methods  of  Tanning. — Modern  System  of  Tanning. 
— Preparation  of  the  Ooze.  The  Leaches. — The  Handlers. — The 
Layers. — Mixed  Tannages. — Tanning  by  Suspension. — The  Sus- 
penders.— Scouring. — Drying  the  Tanned  Butts. — Old  American 
Method. — The  Drying  Loft. — American  Turret  Drier.— Working  of 
the  Turret  Drier.— Influence  of  Light  upon  Leather.— Striking.— 
Rolling  the  Leather. — To  determine  when  Leather  is  Tanned 
throughout. 

Bark  Tanning. — While  being  probably  the  oldest  mate- 
rial used  for  converting  hides  into  leather,  oak-bark 
although  hemmed  in  by  a  host  of  competitors,  still  retains 
its  reputation  as  the  best  known  source  of  tannin  for  the 
preparation  of  sole  leather.  It  is  not  on  account  of  its 
richness  in  tannic  acid,  for  there  are  many  vegetable  sub- 
stances which  yield  a  far  greater  percentage  of  tannin 
than  oak  bark,  but  doubtless  its  great  advantages — which 
are  most  fully  developed  in  the  layers — depend  upon 
the  way  in  which  it  is  employed.  When  ground  oak- 
bark  is  stratified  between  layers  of  skin  deprived  of  its 
cuticle,  hair,  and  flesh,  the  whole  being  saturated  with  an 
infusion  of  the  bark,  not  only  is  the  tannin  gradually  pre- 
sented to  the  surfaces  of  the  skins,  or  pelts,  and  the 
strength  of  the  liquor  maintained  by  the  ground  bark  until 
it  is  exhausted,  but  the  feeding  of  the  leather  with  vege- 
table extractive — which  is  a  slow  and  occult  process — 
takes  place,  whereby  the  leather  is  materially  increased  in 
weight  and  solidity. 

After  the  hides  have  been  subjected  to  all  the  prelimi- 
nary operations  of  soaking,  liming,  unhairing  and^eskingr, 
rounding  and  raising,  the  butts  are  ready  for  the  tanning 


144  LEATHER  MANUFACTURE. 

process;  and  since  this  is  conducted  upon  various  sys- 
tems, it  will  be  necessary  to  treat  of  them  separately, 
commencing  with  the  older  methods,  which,  so  far  as 
regards  the  excellence  of  the  results  obtained,  have  not 
been  surpassed,  even  though  a  host  of  gifted  observers 
have  endeavoured  to  hasten  the  process  without  injury 
to  the  quality  of  the  product.  It  must  be  understood 
that  by  the  process  of  raising,  the  pores  of  the  skin 
become  distended  or  swollen,  by  which  it  more  readily 
absorbs  the  tanning  principle  and  its  associate,  vege- 
table extractive.  In  this  condition  the  butts  are  ready 
for  the  suspenders  or  handlers,  a  series  of  pits  in  which 
the  pelts  receive  their  first  dose  of  tannin  from  weak  infu- 
sions of  bark. 

Old  Methods  of  Tanning. — By  one  of  the  older  methods 
of  tanning,  the  hides  were  limed  in  very  weak  lime 
liquors,  and  the  skins  were  brought  to  a  condition  for  un- 
hairing  and  fleshing  in  about  three  months.  They  were 
then  placed  between  layers  of  coarsely-ground  oak-bark  in 
the  pits,  the  layers  of  hide  and  bark  being  alternately 
formed  until  the  pits  were  full,  when  a  final  stratum  of 
bark  was  placed  over  the  whole ;  no  water  or  other 
liquor  was  allowed  to  enter  the  pits.  After  a  few  weeks 
the  hides  were  transferred  to  another  pit  with  interposed 
layers  of  fresh-ground  bark,  the  top  hide  of  the  first  pit 
being  placed  at  the  bottom  of  the  next  pit  (which  was 
previously  strewn  with  ground  bark)  and  so  on  until  the 
position  of  the  whole  pack  was  reversed.  After  about 
three  months  the  process  was  repeated,  the  spent  bark 
being  substituted  for  fresh  bark  each  time.  These  changes 
were  effected  from  time  to  time  until  the  tanning  was 
completed,  which  generally  occupied  about  eighteen 
months,  or  even  a  still  longer  period. 

An  improvement  in  the  above  very  slow  method  was 
afterwards  adopted  with  great  success.  This  consisted  in 
filling  the  pits,  after  they  had  been  filled  up  with  alternate 
layers  of  hide  and  ground  bark,  with  soft  water;  and 
when  the  tannin  was  found  to  be  exhausted  from  the 
liquor  or  ooze  thus  formed,  the  pits  were  emptied  and 


TANNING  BUTTS  FOR  SOLE  LEATHER.  14$ 

again  filled  with  hides  and  fresh  bark,  and  filled  up  with 
water  as  before,  these  operations  being  repeated  many 
times  during  a  period  of  about  fifteen  months,  at  the  end  of 
which  time  leather  of  most  excellent  quality  was  produced. 

By  another  method,  a  layer  of  spent  bark,  about  six 
inches  thick,  was  first  spread  over  the  bottom  of  the  pit, 
and  over  this  about  an  inch  layer  of  fresh  finely-powdered 
bark  was  placed,  and  upon  this  a  hide  was  spread  perfectly 
flat ;  another  layer  of  fresh  bark  was  spread  over  the  hide, 
then  another  hide  laid  above  this,  followed  by  another 
layer  of  bark,  and  so  on  until  the  pit  was  full ;  the  whole 
pile  was  then  covered  with  a  six-inch  layer  of  bark,  termed 
a  hat.  This  being  done,  the  whole  was  well  trodden 
down  and  sometimes  stout  planks  or  boards,  heavily 
weighted,  were  placed  on  the  upper  surface.  The  pit  was 
then  filled  up  with  a  weak  infusion  of  bark,  or  ooze,  and 
allowed  to  remain  for  two  or  three  months,  when  the  pit 
was  emptied  and  the  hides  were  stretched  and  again 
placed  in  the  pit  with  alternate  layers  of  fresh  bark,  and 
the  pit  again  filled  up  with  ooze  as  before.  After  three 
or  four  months  the  process  was  repeated  several  times,  and 
at  the  last  operation  the  pit  was  filled  with  strong  ooze. 
In  about  fifteen  months  the  leather  was  perfect. 

Sometimes  it  was  the  practice,  under  the  older  systems, 
instead  of  filling  the  pits  with  water  or  ooze,  to  put  a 
little  water  into  the  bottom  of  the  pit,  the  vapour  from 
which,  rising  upward,  promoted  the  absorption  of  tannin 
by  the  skins. 

Modern  System  of  Tanning.— The  practice,  under  the 
modern  system  of  tanning,  is  to  employ  an  infusion  of 
bark  or  other  tanning  material,  instead  of  water,  in  all 
stages  of  the  process,  and  ooze  of  greater  strength  is  used 
than  in  the  older  methods,  whereby  considerable  time  is 
saved  in  the  conversion  of  skin  into  leather.  The  ooze  is 
employed  at  various  degrees  of  strength,  progressively,  the 
strongest  ooze  being  reserved  for  the  last  operation.  The 
tanning  strength  of  the  ooze  is  determined  by  an  instru- 
ment called  the  barkometer,  which  is  described  in  another 
chapter. 


146  LEATHER  MANUFACTURE. 

In  speaking  of  the  modern  system  of  tanning,  as 
distinguished  from  the  older  methods,  we  do  not  wish  it 
to  be  understood  that  an  uniform  system  of  tanning  is 
adopted  by  all  manufacturers  ;  indeed  this  is  so  far  from 
being  the  case  that  it  might  be  more  correct  to  say  that 
each  manufacturer  adopts  a  method  more  or  less  modified 
by  his  own  experience  and  the  discoveries  and  improve- 
ments of  inventors  wjiich  have  from  time  to  time  been 
made  known  to  him.  And  while  some  manufacturers,  in 
every  practical  art,  are  more  desirous  of  seeking  arid 
adopting  useful  improvements  than  others,  it  will 
naturally  follow  that  considerable  progress  may  be  made 
in  some  establishments  whilst  others  continue  to  work  in 
"the  same  old  groove"  until  successful  competition 
renders  a  change  inevitable.  Again,  the  tanner's  is  a  very 
"  close  "  trade,  and  is  conducted  with  an  amount  of  secrecy 
that  almost  bars  improvement,  while  it  certainly  checks 
the  progress  of  the  art  in  this  country.  Jackson  Schultz 
says,  with  much  truth,  "  When  the  English  tanner  shall 
become  as  communicative  as  he  is  at  present  reticent,  the 
whole  world  will  be  enlightened  as  to  the  economy  of 
these  agents,  with  those  in  use  with  tanners  of  the  rest  of 
the  world."  This,  however,  we  can  scarcely  expect  while 
our  American  competitors,  in  the  language  of  Mr.  Schultz, 
"  shoot  at  us  from  behind  a  hedge  of  more  than  30  per 
cent,  import  duty." 

The  process  of  tanning,  as  generally  conducted  at  the 
present  day,  we  will  now  describe,  but  we  recommend  that 
fair  attention  should  be  paid  to  some  of  the  numerous 
mechanical  contrivances  described  in  subsequent  chapters 
which  have  for  their  object  the  uniform  diffusion  of  the 
tannin  throughout  the  whole  of  the  pack  or  series  of 
hides  in  the  earlier  stages  of  the  operation,  as  also  those 
mechanical  devices  which  have  been  designed  to  economise 
the  labour  of  handling. 

Preparation  of  the  Ooze.  The  Leaches. — This  is  con- 
ducted in  vats  or  pits  termed  taps  or  leaches*  These  pits 

*  Also  called  letches  or  latches. 


TANNING  BUTTS  FOR  SOLE  LEATHER.  14? 

are  usually  about  9  feet  square  and  5  feet  deep,  each  one 
being  capable  of  holding  sufficient  liquor  for  two  handlers, 
or  pits  in  which  the  pelts  are  first  treated  with  tan  liquor. 
The  leaches  are  commonly  fitted  with  a  false  bottom,  so  that 
the  liquor  may  be  pumped  or  drawn  off  the  spent  bark  as 
required.  The  ooze  is  prepared  by  placing  a  quantity  of 
ground  oak-bark  in  the  pit,  to  which  cold  water  is  added, 
and  the  liquor  formed  filters  through  the  false  bottom, 
fresh  water  being  introduced  from  time  to  time  until  the 
bark  is  exhausted  of  its  tannin.  Some  tanners  prepare 
their  "  liquors  "  or  ooze  with  hot  or  lukewarm  water,  by 
passing  steam  through  a  large  iron  pipe  to  the  lower  part 
of  a  deep  pit  containing  a  mixture  of  the  bark  and  water. 
A  little  above  the  true  bottom  is  a  false  bottom,  through 
which  the  liquor  filters  into  the  space  below,  and  from 
which  it  is  withdrawn  by  suitable  pumps.  Steam  pumps 
are  now  generally  employed  for  this  purpose,  as  also  for 
transferring  the  liquors  from  one  pit  to  another ;  some  of 
these  pumps  are  capable  of  distributing  as  much  as 
13,000  gallons  of  liquor  per  hour.  By  another  system, 
water  is  first  applied  to  nearly  exhausted  bark,  which 
is  allowed  to  remain  at  a  moderate  heat  for  a  consider- 
able time,  and  the  weak  infusion  thus  obtained  is  pumped 
into  a  pit  containing  bark  somewhat  less  exhausted. 
The  liquor  from  this  second  pit  is  then  transferred  to 
a  third  still  richer  in  tannin,  and  so  on  through  a  series 
of  leaches  until  it  reaches  a  leach  or  pit  containing 
freshly-ground  bark,  from  which  pit  the  liquor  is  with- 
drawn for  use.  The  liquors  or  oozes  are  termed  re- 
spectively handler  liquor  and  layer  liquor,  the  latter  being 
the  stronger. 

The  Handlers. — When  the  butts  have  passed  through 
all  the  preliminary  processes,  they  are  transferred  to  the 
handlers,  a  series  of  pits  7  feet  by  5  feet,  and  5  feet  deep, 
in  which  they  are  treated  with  weak  infusions  of  bark, 
commencing  at  about  15°  to  20°  by  the  barkometer,  being 
handled  twice  a  day  during  the  first  two  or  three  days, 
either  by  turning  them  over  in  the  liquor,  or  by  taking 
them  out  one  by  oiie  and  piling  them  in  a  heap,  and 


148 


LEATHER  MANUFACTURE. 


then  replacing  them  in  reverse  order  in  the  pit.  The 
operation  of  handling  is  shown  in  Fig.  15.  It  is  more 
generally  the  practice,  however,  to  work  the  handlers 
in  what  is  termed  a  round,  which  may  consist  of  six 
pits.  In  the  first  of  the  series  the  washed  butts,  as 
they  come  from  the  beam-house,  are  placed ;  or,  when 
suspenders  are  employed  (to  which  we  shall  presently 


Fig.  15. 

refer),  those  which  have  received  a  preliminary  treatment 
in  these  vats.  The  butts  are  placed  in  the  first  pit,  one 
by  one,  and  are  handled  once  or  twice  a  da}^  by  removing 
them  from  and  returning  them  to  the  same  pit,  after 
which  they  are  shifted  to  the  next,  and  so  on,  through 
the  first  four  pits ;  after  which  they  are  treated  in  the  last 
two  pits  of  the  series  in  this  way  :  the  butts  are  spread 
out  one  by  one  in  the  next  pit,  each  butt  being  sprinkled 
over  with  a  thin  layer  of  finely- ground  oak-bark,  which 
has  the  effect  of  keeping  them  from  absolute  contact, 


TANNING  BUTTS  FOR   SOLE  LEATHER.  M9 

whereby  the  ooze  more  readily  reaches  all  surfaces  of 
the  butts,  and  at  the  same  time  augments  the  strength  of 
the  liquor ;  moreover,  by  this  system  the  feeding  of  the 
skin  with  tannin  and  extractive  matter  is  greatly  aug- 
mented. After  being  thus  treated,  they  are  allowed  to 
remain  for  about  two  days,  when  they  are  removed,  to  allow 
the  introduction  of  fresh  liquor  and  powdered  oak-bark, 
to  which  treatment  they  are  subjected  about  three  times 
a  week.  The  other  packs  follow  in  due  succession,  and 
eventually  the  first  becomes  the  most  advanced,  while  the 
last  pack,  fresh  from  the  beam-house,  becomes  the  first  of 
the  next  round,  and  so  on. 

When  all  the  pits  have  been  worked  in  this  way,  the 
last  pit  eventually  contains  merely  the  stale  sour  liquor 
through  which  all  the  butts  in  the  round  have  succes- 
sively passed.  This  liquor  is  generally  pumped  into  the 
"suspenders,"  where  such  are  employed,  in  which  any 
tannin  that  may  still  be  present  becomes  absorbed  by 

freen  or  fresh  butts,  after  which  the  liquor,  being  ex- 
austed  of  its  tannin,  is  run  oft'  as  waste.  As  each  pit 
becomes  empty,  it  is  cleaned  out  and  recharged  with  fresh 
clear  liquor  or  ooze  from  the  leaches,  the  strength  of 
which  varies  from  20°  to  30°,  according  to  the  practice  of 
the  tanner. 

The  treatment  of  butts  in  the  handlers  generally  occu- 
pies about  six  or  eight  weeks,  by  which  time  the  colouring 
matter  of  the  bark  and  the  tannin  should  have  struck, 
as  it  is  termed,  through  about  one-third  of  the  substance 
of  the  pelt.  By  this  time  the  butts  of  the  oldest  packs 
will  generally  have  become  covered  with  a  peculiar 
bloom,  as  it  is  called,  and  which  is  cllagw  acid,  a  substance 
insoluble  in  water ;  the  substance  of  the  pelt  is  also 
materially  increased  in  weight,  and  is  more  firm  and 
solid.  In  this  condition  the  butts  are  next  removed  to 
the  layers,  in  which  they  receive  the  final  treatment  of 
bark  and  ooze,  in  progressive  stages,  until  the  tanning  is 
complete. 

The  Layers.— In  these  pits,  which  are  termed  fay- 
away  s  by  the  Americans,  the  butts  are  stratified  with 


15^  LEATHER  MANUFACTURE. 

ground  oak-bark,  which  is  carefully  spread  between  each 
butt  to  the  depth  of  about  one  inch.  A  layer  of  bark  is 
first  spread  over  the  bottom  of  the  pit,  and  a  butt  is  then 
laid  over  this,  followed  by  another  layer  of  bark,  then  a 
butt,  and  so  on  until  the  pit  is  full,  a  layer  of  ground  bark, 
called  a  hat,  being  placed  on  the  top.  The  pit  is  then 
filled  up  with  ooze  at  about  30°  to  35°,  more  or  less,  ac- 
cording to  the  practice  of  the  tanner.  The  layer  is  then 
allowed  to  rest  undisturbed  for  five  or  six  weeks,  by 
which  time  the  tannin,  with  extractive  matter,  will  have 
combined  with  the  animal  fibre.  The  butts  are  then  taken 
out,  and  the  spent  bark  and  ooze  removed,  after  which 
they  are  stratified  with  bark  as  before,  and  the  pit  then 
filled,  being  in  this  second  layer  treated  with  ooze  at  about 
40°.  At  the  end  of  about  three  months,  the  butts  are 
again  shifted,  stratified  with  fresh  bark,  and  treated  with 
a  still  stronger  ooze.  About  the  end  of  six  months  from 
the  commencement,  the  thinner  butts  will  have  become 
rfectly  tanned,  while  the  stouter  butts  will  require  to 
treated  again  with  fresh  bark  as  before,  with  ooze  at 
about  60°,  or  even  higher,  and  in  this  layer  they  must 
remain  for  about  six  weeks  or  two  months.  Mr.  Schultz 
strongly  objects  to  the  practice  of  working  butts  of  irre- 
gular thickness  in  the  same  pack,  and  indeed  common 
sense  would  support  his  view,  since  it  is  obvious  that 
while  the  stouter  butts  would  be  imperfectly  tanned,  some 
of  the  thinner  butts,  being  tanned,  would  probably  suffer 
from  prolonged  immersion  in  exhausted  liquor. 

In  shifting  the  butts  from  one  pit  to  another,  the  top 
butt  of  one  pack  becomes  the  bottom  butt  of  the  next,  by 
which  change  of  position  the  action  of  the  tannin  and 
the  effects  of  pressure  become  to  some  extent  equalised 
throughout  the  entire  pack.  There  appears  to  be  no  fixed 
rule  as  to  the  strength  of  ooze,  or  the  period  of  time 
which  should  be  allowed  for  tanning  heavy  butts,  since 
each  tanner  adopts  a  method  of  his  own  ;  indeed,  in  this 
as  in  every  other  branch  of  the  art,  there  appears  to  be 
considerable  difference  in  practice — personal  judgment 
rather  than  fixed  rule  being  the  chief  guide  in  most  of  the 


TANNING  BUTTS  FOR  SOLE  LEATHER.  151 

operations  of  the  tanner.     A  general  view  of  the  tan-pits 
is  given  in  the  engraving  Fig.  16. 

Mixed  Tannages. — As  to  the  materials  employed  in 
butt  tanning,  there  is  considerable  difference  in  practice 
at  the  various  tanneries.  While  some  tanners  prepare  their 
liquors  entirely  from  oak-bark,  others  use  valonia  for  their 
liquors,  and  employ  ground  bark  only  for  sprinkling,  or 
"dusting"  in  the  handlers;  other  tanners  employ  two- 
thirds  valonia  to  one-third  myrobalans  in  making  their 
liquors,  or  one-half  valonia  to  one-fourth  each  mimosa  and 
myrobalans.  Divi  divi  is  not  extensively  used  in  butt 
tanning  owing  to  its  liability  to  induce  fermentation  ;  but 
since  it  is  a  cheap  material  and  is  reputed  to  give  good 
weight  to  the  butt,  there  is  a  natural  desire  to  employ  it 
as  far  as  can  be  done  with  safety,  with  or  without  the  use 
of  antiferments.  In  some  tanneries,  divi  divi  is  used  in 
small  proportions  with  each  tap  or  leach,  by  placing  it 
beneath  the  other  tanning  materials,  so  as  to  keep  it  as 
far  as  possible  from  the  air.  If,  however,  its  suscepti- 
bility to  fermentation  is  due  to  mucilaginous  or  other  vege- 
table matter  (which  is  most  probable),  its  exclusion  from 
the  air  would  not,  we  should  think,  be  of  much  conse- 
quence ;  but  its  tendency  to  promote  this  decomposition 
might  be  more  readily  checked  by  employing  one  or  other 
of  the  substances  which  have  been  found  most  effective 
in  arresting  gallic  fermentation. 

Valonia  is  an  important  tanning  material,  but  when  used 
alone  it  imparts  an  objectionable  colour  and  harshness 
to  the  leather;  it  is  therefore  most  generally  employed  with 
a  moderate  proportion  of  myrobalans.  An  excess  of  the 
latter  would  be  mischievous,  since  they  are  considered  liable 
to  promote  gallic  fermentation.  Mimosa  is  much  used  to 
modify  the  colour  of  valonia,  since  it  imparts  an  agreeable 
pinkish  tinge  to  the  leather  which  is  generally  approved. 
Being  a  powerfully  astringent  substance,  while  yielding  a 
strong  colour,  it  can  only  be  used  in  moderate  proportions. 
The  tannin  of  this  material  requires  to  be  extracted  by 
boiling  water — steam  heat  being  generally  employed — 
and  the  liquors  are  usually  prepared  in  separate  pits. 


TANNING  BUTTS  FOR  SOLE  LEATHER.  *53 

Mimosa  liquors  are  not  so  susceptible  of  gallic  fermenta- 
tion as  the  tannins  obtained  from  some  other  materials,  as 
divi-divi,  for  example.  Gambier,  or  terra  japonica,  is  fre- 
quently added  to  the  handler  liquors  in  moderate  propor- 
tions, and  is  specially  useful  in  keeping  up  the  tanning 
strength  of  the  liquors.  Of  the  many  new  tanning  extracts 
which  are  now  largely  imported  into  this  country,  oak- 
wood,  chestnut,  hemlock,  and  mangrove  are  prominent, 
and  the  two  former  have  now  firmly  established  them- 
selves into  favour ;  but  it  will  probably  be  a  very  long 
time  before  any  English  tanner  will  use — from  choice— 
any  tanning  material  but  oak-bark  for  the  preparation  of 
the  best  quality  of  sole  leather.  Indeed,  while  the  tan 
colour  of  oak-bark  remains  the  accepted  colour  of  the  best 
English  leather,  it  will  be  difficult  to  induce  the  trade  to 
recognise  any  leather,  as  of  the  best  oak-bark  tannage, 
which  presents  a  different  tint  to  that  to  which  they  have 
been  so  long  accustomed. 

Tanning  by  Suspension. — In  some  tanneries  it  is  the 
practice  to  suspend  the  hides  in  weak  tanning  infusions 
before  they  are  treated  in  the  handlers.  The  object  of 
this  system  is  to  ensure  the  uniform  absorption  of  tannin 
by  the  pelts  before  subjecting  them  to  the  rough  usage  of 
handling,  which  in  the  early  stages  of  the  process  is  liable 
to  cause  injury  to  the  delicate  structure  of  the  pelt.  It 
will  be  readily  understood  that  after  the  pelt  has  become 
partially  tanned  it  is  less  susceptible  of  injury,  and  any 
method,  therefore,  which  will  effect  this  object  without 
subjecting  the  delicate  texture  of  the  unhaired  skin  to 
the  chances  of  abrasion,  or  to  the  rough  treatment  of  iron 
hooks,  must  be  advantageous.  When  the  hides  have  become 
partially  tanned,  they  are  more  capable  of  bearing  without 
injury  the  rougher  treatment  which  handling,  however 
carefully  conducted,  necessarily  involves. 

The  Suspenders. — There  have  been  many  ingenious 
contrivances  introduced  for  suspending  hides  in  the  tan 
liquors,  both  in  the  earlier  stages  of  the  process  and  also 
for  the  complete  tanning  of  hides,  the  latter  of  which 
will  be  described  hereafter.  In  one  form  of  suspender 


154  LEATHER  MANUFACTURE. 

a  stout  wooden  shaft  is  placed  across  the  pit  lengthwise, 
being  partially  immersed  in  the  liquor ;  to  this  shaft  about 
20  hides  are  attached,  one  above  another.  When  the 
shaft  revolves,  the  first  or  upper  hide  becomes  lowered 
into  the  liquor,  followed  by  the  second  and  third,  and  so 
on,  the  entire  pile  of  hides  becoming  unfolded  as  it  were, 
and  one  by  one  lowered  into  the  liquor ;  as  the  shaft  con- 
tinues to  revolve,  the  hides  become  alternately  exposed  to 
the  air  and  the  tan  liquor.  Doubtless  it  would  be  an 
improvement  if  the  hides  could  be  kept  under  the  liquor 
the  whole  time;  still  the  exposure  to  the  air  is  only 
momentary,  and  certainly  much  less  than  in  the  ordi- 
nary system  of  handling.  By  this  method  the  butts 
would  undoubtedly  be  constantly  exposed  to  fresh  sur- 
faces of  tan  liquor — a  most  important  point  to  be  reached 
in  all  processes  of  immersion  in  which  chemical  action 
plays  a  part. 

The  American  Rocker  Handler,  described  in  another 
chapter,  is  much  adopted  in  the  United  States,  and  is,  we 
believe,  used  to  some  extent  in  this  country.  But  although 
in  the  early  stages  of  tanning,  when  the  object  is  to  im- 
pregnate the  skins  throughout  with  a  moderate  amount  of 
tannin,  the  practice  of  keeping  the  hides  in  motion  while 
in  the  weak*  liquors  is  doubtless  advantageous,  in  the 
latter  stages  the  reverse  treatment  appears  to  be  accepted 
as  that  which  is  most  favourable  to  the  proper  feeding  of 
the  hide  and  the  production  of  good  leather.  This  fact 
was  established  by  the  older  tanners  and  recognised  by 
Sir  Humphry  Davy  and  all  observers  of  eminence  who 
had  studied  the  subject.  In  support  of  this,  Jackson 
Schultz  says,  "  Leather  tanned  while  at  rest  will  have  a 
firmer  texture  than  if  motion  is  used  to  aid  the  tanning. 
This  would  probably  be  the  testimony  of  the  butt  tanners 
of  Great  Britain,  and  there  is  much  in  our  own  experience 
to  confirm  such  a  view  of  the  case."  Indeed,  when  we 
reflect  that  not  only  tannin  but  vegetable  extractive  enters 

*  If  the  pelts  were  immersed  in  strong  ooze  at  first,  they  would  become 
case-hardened,  as  it  is  termed,  in  which  state  they  would  offer  great 
resistance  to  the  further  absorption  of  tannin. 


TANNING  BUTTS  FOR   SOLE  LEATHER.  155 

into  the  composition  of  sound  leather,  it  will  at  once  be 
apparent  that  this  substance — not  having  the  same  affinity 
for  gelatine  as  tannin — would  necessarily  require  a  con- 
dition  cf  rest  to  enable  it  to  combine,  even  in  small 
quantity,  with  materials  which  have  so  powerful  an  affinity 
for  each  other.  To  feed  the  leather  properly,  therefore, 
rest  during  a  greater  portion  of  the  time  required  for 
tanning  is  an  absolute  necessity  in  the  preparation  of 
what  is  known  as  leather — that  is,  not  merely  a  spongy 
compound  of  tanno-gelatine  plus  colouring  matter,  which 
frequently  passes  under  that  name,  but  leather  properly 
so-called. 

After  the  butts  are  removed  from  the  layers,  it  is  some- 
times the  practice  to  throw  them  into  pits  containing  weak 
tan  liquor,  and  then  to  take  them  out  one  by  one,  and 
brush  them  all  over  to  remove  particles  of  spent  tan  which 
may  have  adhered  to  them  ;  they  are  then  laid  across  a 
beam  called  the  horse  to  drain.  It  is  usual  at  this  stage — 
especially  with  butts  of  the  best  bark  tannage — to  strike 
them  with  the  pin  (Fig.  18)  while  still  moist,  to  remove 
the  Lloom  ;  but  sometimes  this  is  effected  by  laying  the 
butt  flat  on  the  scour  ing- table  and  rubbing  it  with  a 
stone  called  the  scour  ing-stone,  a  tool  provided  with 
two  sharp  edges  produced  by  working  on  a  grindstone. 
With  this  tool  the  workman  removes  every  trace  of 
bloom  from  the  grain  side  of  the  leather.  The  grain 
side  is  next  rubbed  over  with  a  damp  cloth,  then  with  a 
dry  one,  and  afterwards  linseed  oil  is  rubbed  over  the 
grain  to  prevent  the  too  rapid  drying  of  this  surface  of 
the  leather. 

Scouring. — This  is  sometimes  effected  by  scouring- 
machines,  one  of  which,  the  "  Burdon  "  scourer,  is  shown 
in  Fig.  17.  See  also  Fig.  66,  p.  408.  After  scouring  it 
is  sometimes  the  practice  to  strike  the  leather  with  the 
pin  to  lay  the  grain,  and  after  this  the  grain  side  is 
oiled,  and  the  butts  then  sent  to  the  loft,  where  they  are 
hung  up  and  allowed  to  remain  until  partially  dried ;  they 
are  then  taken  down,  the  flesh  and  grain  sides  slightly 
damped,  and  the  butts  are  next  piled  in  a  heap  to  sam,  or 


I56 


LEATHER  MANUFACTURE. 


samm,  as   it  is  termed,  for  several   days,  by  which  the 
leather  becomes  tempered,  or  in  an  uniformly  moist  and 


Fig.  17. 

softened  condition.  In  this  state  it  is  ready  for  the  first 
rolling  operation,  which  will  be  described  further  on. 

Drying  the  Tanned  Butts.— Although  apparently  a 
simple  process  in  itself,  much  skill  and  judgment  on  the 
part  of  the  workman  are  required  to  dry  recently  tanned 
skins  properly.  If  the  drying  be  too  slow,  especially  in 
damp  weather,  the  leather  is  apt  to  mould,  which  is  very 
injurious  to  it ;  if,  on  the  other  hand,  the  drying  be  too 
quick,  or  the  leather  is  exposed  to  the  direct  rays  of  the 
sun,  it  is  liable  to  become  discoloured,  hard,  and  brittle. 
A  well- ventilated  loft,  in  which  the  skins  may  be  exposed 
to  a  gentle  but  continuous  current  of  air,  without  being 
subject  to  the  direct  solar  rays,  is  considered  most  favour- 
able for  uniform  and  perfect  drying. 

Old  American  Method. — The  skins,  when  sufficiently 
tanned,  are  taken  from  the  pits  without  being  shaken  or 


TANNING  BUTTS  FOR   SOLE  LEATHER.  157 

beaten,  and  are  stretched  on  pegs  or  hung  up  by  their 
heads  from  large  nails,  each  one  being  kept  expanded  by 
two  or  three  sticks  passed  through  from  side  to  side, 
so  that  all  parts  may  be  uniformly  exposed  to  the  air. 
When  they  have  begun  to  whiten,  and  have  become 
slightly  stiff,  but  before  they  are  perfectly  dry,  they  are 
stretched  out  upon  a  clean  place  and  scoured  with  the 
spent  tan  with  which  they  are  still  covered.  "When  well 
cleaned  in  this  way,  they  are  then  to  be  trodden  out  and 
beaten  with  the  soles  of  the  feet  in  every  direction  upon 
both  sides  ;  and  after  the  inequalities  and  protuberances 
of  surface  have  been  made  to  disappear  by  the  flatten- 
ing process,  they  are  assorted  in  sizes  and  piled  up  in 
heaps.  While  the  skins  are  stretched  in  the  drying- 
room  they  should  be  beaten  twice  daily,  morning  and 
evening,  upon  the  flesh  side  with  a  round-faced  wooden 
mallet.  If  the  skins  should  be  dry,  the  operation  may  be 
facilitated  by  moistening  their  surface  with  a  wet  brush. 
This  process  imparts  firmness,  but  the  operations  are  now 
almost  entirely  done  by  machinery. 

The  Drying  Loft,  or  Shed,  as  it  is  sometimes  called, 
is  a  capacious  wooden  structure,  one  or  more  stories  high, 
according  to  the  extent  of  the  works.  It  is  provided  with 
a  series  of  openings  all  round  the  apartment,  through 
which  the  wind  from  any  quarter  can  pass  freely,  and 
thus  traverse  through  the  suspended  hides.  These  openings 
are  protected  by  weather-boards,  or  trap  doors,  which  can 
be  placed  at  such  an  angle  that  while  the  air  may  be  admitted 
as  required,  the  direct  rays  of  the  sun  can  be  prevented  from 
reaching  the  leather.  The  circulation  of  air  is  further 
aided  by  a  portion  of  the  flooring  being  composed  of 
narrow  boards  placed  at  a  certain  distance  (about  2  inches) 
apart  from  each  other,  whereby  air  is  admitted  from 
below  as  well  as  at  the  sides  and  ends  of  the  shed.  To 
facilitate  the  drying,  especially  in  cold  and  damp  weather, 
a  series  of  4-inch  flanged  iron  pipes,  for  steam  or  hot  air, 
are  fixed  above  the  floor,  this  range  of  piping  extending 
all  round  the  interior  of  the  shed.  These  pipes  are  fre- 
quently heated  by  waste  steam  from  the  boiler.  Although 


158  LEATHER  MANUFACTURE. 

this  system  of  artificial  drying  is  by  some  persons  be- 
lieved to  be  injurious  to  the  leather,  on  the  ground 
that  the  heat  dries  the  air,  it  must  be  borne  in  mind 
that  the  moisture  given  off  even  from  merely  damp 
hides  would  be  amply  sufficient  to  compensate  for  the 
natural  moisture  expelled  by  the  heat  from  the  steam- 
pipes.  When  the  drying  of  the  hides  is  near  completion, 
however,  greater  caution  would  undoubtedly  be  neces- 
sary in  subjecting  them  to  the  continued  action  of  hot-air 
pipes. 

The  hygroscopic  condition  of  the  air — that  is,  the  presence 
or  absence  of  moisture — may  be  determined  by  means  of  an 
instrument  called  the  hygrometer,  of  which  there  are  several 
different  forms.  "Mason's  hygrometer  shows  the  relative 
dryness  and  moisture  of  the  atmosphere  by  the  degree  of 
cold  produced  by  evaporation  from  a  given  surface.  If 
two  delicate  thermometers  have  their  bulbs  covered  with  a 
thin  piece  of  muslin,  and  if  the  one  be  dry  and  the  other 
moist,  the  depression  of  the  latter  will  be  directly  as  the 
rapidity  or  amount  of  evaporation,  and  this  again  will 
chiefly  depend  upon  the  state  of  the  circumambient  air  as 
to  moisture ;  if  it  be  charged  with  vapour,  no  evapora- 
tion from  the  wet  bulb  will  ensue,  and  consequently  the 
mercury  in  that  thermometer  will  remain  stationary  ;  if, 
on  the  contrary,  the  air  be  very  dry,  it  will  eagerly  ab- 
stract vapour  from  the  humid  surface,  and  a  corresponding 
degree  of  cold  will  be  indicated  by  the  depression  of  the 
mercury  in  the  humid  thermometer  as  compared  with  the 
standard  or  dry  thermometer." — Brande. 

To  roughly  determine  whether  the  drying  of  the  leather 
is  complete  in  an  apartment  heated  by  steam  or  hot-air 
pipes,  a  small  pocket  looking-glass,  previously  kept  in  a 
very  cold  situation,  might  be  used.  If  the  glass  be  held 
about  half  an  inch  from,  or  nearly  touching,  the  suspended 
leather,  if  moisture  be  still  given  off  from  its  surface  this 
will  be  at  once  condensed  on  the  face  of  the  glass,  as  if 
it  had  been  breathed  upon;  if  the  reverse  is  the  case 
(provided  that  the  glass  be  cold)  it  may  be  concluded  that 
the  leather  is  perfectly  dry. 


TANNING  BUTTS  FOR  SOLE  LEATHER.  159 

In  some  tanneries  the  drying  sheds  have  been  heated 
by  hot-water  apparatus  in  place  of  steam,  and  we  believe 
with  success. 

About  G  feet  above  the  floor  of  the  drying-loft  a  series 
of  rafters  are  fixed,  and  upon  these  are  laid  the  wooden 
poles,  called  "shed  poles,"  from  which  the  hides  are 
suspended.  These  poles  are  simply  timber  from  which 
the  bark  has  been  removed ;  they  average  about  2|  inches 
in  thickness,  and  are  from  6  to  8  feet  in  length. 

American  Turret  Drier. — A  brief  description  of  the 
American  "  turret  drier  "  will  prove  interesting  to  those 
who  may  be  desirous  of  modifying  their  present  method  of 
drying,  or  may  require  an  extension  of  their  present  drying 
arrangements.  The  following  is  abridged  from  Mr.  Jackson 
Schultz's  admirable  description  of  the  turret  drier :  The 
building  may  be  any  number  of  stories  high,  some  being 
three  or  four,  while  others  are  seven  or  eight.  Mr. 
Schultz,  however,  recommends  but  five  stories,  each  about 
7  feet  clear  between  the  beams,  or  high  enough  for  a  man 
to  pass  with  his  hat  on.  Such  a  building  need  not  be 
made  of  very  heavy  timber,  and  therefore  would  be  in- 
expensive as  compared  with  higher  structures.  The 
building  should  be  about  two  spans  of  timber — say  40  feet 
— wide,  with  two  rows  of  posts  equidistant  from  the  sides. 
Longitudinally  with  these  rows  of  posts  should  run  a  light 
board  partition,  with  intersections  at  every  10  feet,  ex- 
tending to  the  sides.  This  would  cut  the  space  up  into 
two  rows  of  rooms  about  10  by  12  feet  each,  with  a  centre 
passage  of  about  13  feet.  The  roof  is  made  of  the  usual 
latticed  lantern  form  from  end  to  end.  All  the  floors 
above  the  ground-floor  should  be  latticed,  and  the  rooms 
would  of  course  be  immediately  above  each  other,  so  that 
if  the  building  were  five  stories  high,  there  would  be  five 
rooms,  10  by  12  each,  standing  one  above  another,  and 
there  should  be  just  as  many  of  these  rooms  as  would  dry 
the  stock  of  the  yard.  The  centre  passage-ways  should 
be  lighted  by  cross-sections  leading  to  the  windows,  and 
each  room  should  contain  one  small  window  close  to  the 
top  to  admit  light  only.  There  should  be  no  openings 


160  LEATHER  MANUFACTURE. 

except  at  the  base  of  the  lower  room,  with  the  air  leading 
directly  on  the  piping. 

Each  room  will  hold  one  pack  of  100  or  120  hides, 
depending  upon  the  weight  of  leather,  and  will  dry  the 
same  in  ten  days.  The  rooms  on  the  first  floor  should  be 
supplied  with  steam-pipes  laid  on  the  floor,  or  raised 
only  a  few  inches  above  it.  The  heating  of  the  pipes 
should  be  under  separate  control,  so  that  any  degree  of 
heat  can  be  admitted,  and  the  steam  turned  on  or  off  at 
pleasure. 

Working  of  the  Turret  Drier. — All  the  packs  taken 
out  in  one  day,  or  in  two  or  more  days  in  succession, 
should  go  into  one  of  these  sections,  so  that  the  condition 
of  the  leather  may  be  as  nearly  uniform  as  possible  in  each 
set  of  rooms.  The  leather  is  hung  upon  sticks,  in  double 
rows,  leaving  a  passage  of  nearly  two  feet  between.  No 
steam  should  be  allowed  to  enter  the  pipes  or  the  section 
during  the  first  three  or  four  days,  neither  should  the 
trap-doors,  which  lead  outwardly,  be  opened  but  slightly 
except  in  warm  weather,  or  when  the  wind  blows  high  ; 
but  in  autumn,  or  during  overcast  weather,  the  lower 
trap-doors  may  be  safely  left  open.  About  the  third  or 
fourth  day  a  low  degree  of  steam  heat  may  be  applied, 
and  gradually  increased  until  the  seventh  to  the  tenth  day, 
by  which  time  the  leather  should  be  fully  dried.  All  the 
hides  in  both  tiers  and  in  all  the  five  rooms  will  have  dried 
in  about  the  same  time,  and  may  be  replaced  by  others. 
Mr.  Schultz  says,  "  One  of  the  best  guides  that  I  can  give 
for  the  capacity  and  practical  working  of  these  driers  in 
connection  with  a  tannery  is  this :  one  of  these  sections 
should  be  large  enough  to  hold  one- tenth  of  ten  days' 
work.  I  have  known  turrets  so  actively  worked  as  to 
turn  out  stock  in  seven  days  ;  but  I  prefer  ten,  since  it  is 
very  important  not  to  hurry  the  drying  during  the  first 

few  days The  turret  drier  is,  beyond  all  question, 

the  most  efficient  and  artistic  method  yet  devised  for 
drying  leather,  and,  in  some  of  its  modified  forms,  should 
be  adopted  by  all  tanners.  The  difference  in  the  tempera- 
ture at  the  ground  and  at  an  altitude  of  40  or  50  feet 


TANNING  BUTTS  FOR   SOLE  LEATHER.  161 

would  of  itself  create  a  draught,  as  is  well  illustrated  by 
the  erection  of  stacks  or  chimneys  for  the  passing  off  of 
smoke  or  gas.  But,  if  to  this  natural  action  of  the  differ- 
ence of  temperature  we  add  a  little  steam  heat,  a  steady 
yet  moderate  circulation  will  be  maintained  from  the 
bottom  toward  the  top  or  opening  of  this  structure,  carry- 
ing upward  and  off  the  dampness  from  the  leather,  without 
creating  such  violent  currents  of  air  as  to  stain  and  injure 
the  colour." 

Mr.  Schultz  says  that  it  is  believed  that  the  principle 
of  the  above  method  of  drying  sole  leather  could  be 
applied  with  equal  advantage  to  all  other  kinds  of 
leather ;  and  indeed,  when  we  consider  that  the  gentle 
motion  of  the  heated  air — constantly  ascending  as  it 
does  from  the  steam-pipes — must  keep  up  a  continued 
circulation  of  the  air  within  the  drying-rooms,  this 
should  be  the  most  favourable  condition  under  which  even 
the  most  delicate  leathers  could  be  dried,  provided  that 
the  temperature  were  kept  as  low  as  possible  to  effect  the 
object. 

For  the  purpose  of  conveying  the  hides  to  and  from  the 
drying-rooms,  lifts  or  elevators  are  employed,  which  may 
be  of  any  approved  construction  ;  but  Mr.  Schultz  speaks 
very  highly  of  an  endless  chain  elevator  which  he  strongly 
recommends  to  all  tanners.  This  consists  of  an  endless 
chain,  running  from  the  extreme  bottom  to  the  top  floor, 
ending  under  the  roof.  The  chain  runs  in  a  wooden  box 
enclosed  on  three  sides.  The  open  or  outer  side  serves  to 
attach  the  hides  by  means  of  hooks  fixed  to  the  links  of 
the  chain  at  a  distance  of  about  4  feet.  The  distance 
between  the  attaching  hooks  should  be  sufficient  to  enable 
the  workmen  to  attach  below,  and  take  off"  above,  the  sides. 
By  this  simple  method  leather  may  be  elevated  with  no 
more  actual  expense  than  if  dried  on  the  ground-floor,  and 
the  hides,  when  once  hung,  remain  until  fully  dried,  thus 
saving  all  the  expense  of  "  shifting,"  &c. 

Influence  of  Light  upon  Leather. — The  influence  of 
light  upon  the  colouring  matter  and  juices  of  vegetable 
substances  is  well  known  ;  and  while  this  is  not  so  marked 

M 


162  LEATHER  MANUFACTURE. 

when  such  matter  is  diffused  through  the  cellular  structure 
of  the  plants — by  which  it  is  protected  from  the  action  of 
light  in  some  degree — if  the  vegetable  substance  be  cut  or 
otherwise  injured,  a  discoloration  or  darkening  of  the  part 
takes  place  rapidly  afterwards.  This  is  very  noticeable 
when  we  remove  the  epidermis  or  bark  from  a  growing 
plant ;  the  exposed  surfaces  soon  assume  a  darkish  colour, 
which  increases  in  depth  by  further  exposure.  Probably 
absorption  of  oxygen  may  also  influence  the  result.  The 
fact  is  specially  recognisable  in  the  case  of  the  walnut,  the 
green  covering  of  which  is  well  known  to  impart  a  deep 
brown  stain  to  the  fingers.  The  same  may  also  be  said  of 
young  potatoes,  in  removing  the  skin  from  which  the 
domestic  servant  frequently  finds  the  tips  of  her  fingers 
embellished  by  a  brown  stain.  Now  in  the  preparation  of 
oozes,  or  infusions  of  bark,  the  ground  material,  fresh 
from  the  mill,  is  steeped  in  water — either  warm  or  cold — 
and  while  the  tannin  most  readily  enters  into  solution, 
vegetable  extractive  and  colouring  matter  also  become  dis- 
solved in  the  menstruum.  Now,  what  we  wish  to  suggest 
as  the  cause  of  the  newly  tanned  leather  becoming  dark- 
ened by  exposure  to  air  and  strong  light  is  this  :  that  the 
vegetable  tissue  in  which  the  greatest  amount  of  astrin- 
gent property  lies  (the  part  which  was  nearest  the  wood) 
also  contains  colourable  matter  which  has  not  yet  been 
fully  exposed  to  the  action  of  strong  light,  and  that  an 
infusion  of  this  matter  must,  in  the  ordinary  course  of 
things,  become  darkened  by  exposure  to  light.  And  further, 
that  when  hides  are  steeped  for  a  more  or  less  lengthened 
period  in  such  infusion,  the  leather  produced  must  be 
acted  upon  and  become  discoloured,  or  darkened  in  colour, 
by  exposure  to  light,  more  especially  while  in  a  moist 
condition. 

Schultz  says,  "  Leather  dried  in  the  open  air  will  cer- 
tainly dry  dark,  even  if  tanned  with  pure  oak,  and  if 
tanned  with  hemlock,  or  a  mixed  bark,  will  darken  to  a 
damaging  extent.  If  currents  of  air  reach  the  leather 
while  in  a  wet  state,  a  like  result  is  produced,  with  the 
addition  of  great  harshness  of  grain.  If  a  bright  light, 


TANNING   BUTTS  FOR  SOLE  LEATHER.  163 

particularly  if  the  sun's  rays  reach  the  grain  or  flesh,  the 
acid  of  the  leather  turns  brown,  and  is  permanently  dis- 
coloured. The  influence  of  the  direct  rays  of  the  sun,  or 
even  the  strong  light  of  the  sun,  on  vegetation  is  a  good 
illustration  of  these  influences  on  the  colour  of  leather 
containing  vegetable  acid  in  solution.  The  ordinary  table 
celery  is  covered  with  earth  as  fast  as  it  grows  to  the 
surface  to  keep  the  light  from  it,  so  that  it  may  be  white 
and  tender.  Grass  that  grows  under  cover,  excluded  from 
light,  is  white,  not  green.  This  law  of  light  applies  to 
all  vegetation.  Availing  ourselves  of  this  principle  of 
light,  we  say  that  leather  that  is  intended  to  be  fair  should 
be  dried  in  the  dark,  and  as  free  as  possible  from  currents 
of  air." 

Although,  as  we  have  said,  we  believe  that  light  has 
a  powerful  influence  upon  the  vegetable  matter  absorbed 
by  the  hide,  we  believe  that  the  oxygen  of  the  air  also 
plays  an  important  part  in  this  discoloration,  or  rather 
coloration,  since  from  the  examples  we  have  given, 
light  alone  could  scarcely  have  produced  the  effect.  The 
scratched  rind  of  the  green  walnut  produces  an  almost 
instantaneous  stain,  which  may  be  partially,  if  not 
wholly,  due  to  oxidation;  while  the  celery  referred  to 
by  Mr.  Schultz  would  doubtless  (if  not  protected  by  earth- 
ing up)  acquire  its  natural  green  colour  by  the  action  of 
light  only. 

Striking. — When  the  hides  are  partially  dried,  as  we 
have  before  observed,  they  are  submitted  to  the  operation 


Fig.  18. 

known  as  striking,  which  is  accomplished  with  ihestriJcwg- 
pin  (Fig.  18)  a  two-handled  tool  of  triangular  form  present- 


164  LEATHER  MANUFACTURE. 

ing  three  blunt  edges.  A  section  of  the  blade  of  the  tool 
is  also  shown.  The  butt  is  thrown  across  a  horizontal  convex 
beam,  called  the  horset  and  the  workman,  taking  the  tool 
by  its  handles,  presses  it  firmly  over  the  grain  side  of  the 
leather,  until  the  entire  surface  has  been  gone  over. 
Fig.  19  represents  a  workman  in  the  act  of  striking  a  butt. 
To  economise  labour  in  this  operation  several  forms  of  strik- 


Fig.  19. 

ing-machines,  worked  by  steam,  have  been  introduced. 
The  accompanying  drawing  (Fig.  20)  represents  the 
striking-machine  of  Messrs.  Huxham  and  Browns,  and 
Fig.  66  that  of  Messrs.  Wilson,  the  latter  being  generally 
used  in  British  yards  for  butts  and  bends.  It  is  stated 
that  leather  struck  in  these  machines  acquires  a  solidity 
and  firmness  superior  to  that  of  hand  work,  while  it  also 
enables  the  tanner  to  do  with  less  rolling.  The  workman, 
by  a  weighted  adjustable  foot  lever,  regulates  the  pressure 
instantaneously,  so  that  no  part  of  the  leather  remains 
untouched.  Although  hand  striking  is  still  much  applied, 
there  can  be  little  doubt  that  in  this,  as  in  many  other 
operations  of  the  tanner,  machinery,  from  the  rapidity 


TANNING  BUTTS  FOR  SOLE  LEATHER. 


165 


of  its  action,  will  eventually  supersede  hand  labour  to 
a  great  extent. 


II  illillliiiiiiiiiiiiiiiiiiiiii 


Fig.  20. 

Boiling  the  Leather. — "When  the  butts  are  partially 
dried,  they  are  submitted  to  the  first  operation  of  rolling. 
For  this  purpose  hand  or  steam  rollers  are  used.  The 
hand  machine  consists  of  a  brass  cylinder  or  roller,  sur- 
mounted by  a  heavily  weighted  box-truck,  and  furnished 
with  a  long  handle.  The  butt  is  laid  flat  upon  a  solid  and 
level  wooden  bed  coated  with  metal  (zinc  or  brass  being 
generally  used),  and  the  workman  passes  the  roller  back- 
wards and  forwards  until  every  part  of  the  butt  has  been 
repeatedly  passed  over.  Fig.  21  shows  the  method  of 
using  the  hand  roller.  After  the  first  rolling,  the  butt  is 
again  hung  up  to  become  further  dried,  when  the  oiling 
and  rolling  are  repeated,  and  if  necessary,  the  two  surfaces 
of  the  butt  are  moderately  damped  each  time  before 
repeating  the  rolling.  There  are  many  ingenious  and 
effective  machines  for  steam  rolling,  which,  as  will  be 
readily  understood,  effect  a  great  saving  in  labour,  besides 
being  more  uniform  in  their  action  than  could  be  expected 


166 


LEATHER  MANUFACTURE. 


from  the  smaller  or  hand  machine.      In  Fig.  22  is  shown 
a  rolling-machine  as  supplied  by  Huxham  and  Browns. 


Fig.  21. 

The  roller  is  hung  upon  strong  springs,  which  allows  it 
to  adjust  itself  to   inequalities  in  the  thickness  of  the 


rig.  22. 

leather.      "When   in  use,  the  leather  is    laid  flat   on  an 
ordinary  zinc  or  brass  bed,  as  in  hand  rolling,  and  the 


TANNING  BUTTS  FOR  SOLE  LEATHER. 


167 


roller  passed  over  it,  so  as  to  avoid  the  stretching  and 
cockling  of  the  leather  which  it  is  said  some  machines 
are  liable  to  cause.  Fig.  23  represents  the  American 
Pendulum  Roller.  It  is  said  to  be  especially  suitable  for 
leather  requiring  heavy  rolling,  such  as  buffalo,  kip  hides, 
&c.  Speaking  of  this  machine,  Schultz  says  that  it  is 
claimed  that  if  used  at  its  full  pressure  the  machine  has  a 
sufficient  power  to  actually  cut  the  leather  in  half.  It  is, 


Fig.  23. 

however,  fitted  with  adjustable  spring  bearings,  enabling 
the  roll  to  adjust  itself  to  unequal  thicknesses  in  the 
leather,  and  the  pressure  may  be  regulated  at  will. 

To  determine  when  Leather  is  Tanned  throughout. — 
This  is  ascertained  by  making  a  clean  cut  with  a  sharp 
knife  in  the  stoutest  part  of  a  butt,  when,  if  the  tanning 
is  complete,  the  leather  exhibits  an  uniform  colour 
throughout  its  entire  substance;  if,  on  the  contrary,  a 
light-coloured  streak  is  visible  in  the  interior,  the  process 
is  not  complete,  arid  the  butts  must  be  submitted  to 
further  treatment  in  the  layers  until  the  proper  point  is 
reached — a  perfectly  uniform  colour  throughout  the  entire 
substance  of  the  skin.  Beyond  this  point,  however,  the 
further  steeping  of  the  butts  can  do  no  good,  and  may 
therefore  possibly  do  mischief  in  proportion  to  the  length 
of  what  may  be  termed  unnecessary  time  they  may  be 


1 68  LEATHER  MANUFACTURE. 

immersed  in  the  tan  liquor.  The  aim  of  many  tanners 
appears  to  be  to  ensure  a  good  bloom  upon  their  leather — 
as  a  guarantee,  we  presume,  that  it  has  been  bark-tanned 
by  a  gradual  and  not  by  a  quick  process ;  but  when  the 
perfect  and  complete  tanning  is  effected,  protracted 
immersion  in  the  pits,  merely  to  increase  the  deposit  of 
ellagic  acid  or  bloom,  to  give  an  appearance  to  the 
leather  which  cannot  enhance  its  durability,  would  appear 
a  mistaken  practice,  and  one  which  the  American  tanners 
— who  are  making  great  progress  in  the  art — seem  to 
ignore. 


CHAPTER  XIII. 
TANNING  PROCESSES. 

The  first  English  Patents  for  Tanning.— Newton's  Tanning  Process.— 
Aldrich's  Process. — Orgereau's  Process. — Jennings's  Process.—  Bal- 
latschano  and  Trenk's  Process. — Lomas's  Process. — Michel,  Kollen, 
and  Hertzog's  Process.— Keasley's  Process. 

As  in  the  case  of  every  other  art,  innumerable  patents 
have  been  obtained,  both  at  home  and  abroad,  for  improve- 
ments in  the  processes  of  tanning,  and  for  the  machinery 
and  implements  employed  therein,  besides  many  others 
for  inventions  more  or  less  connected  with  the  manufac- 
ture of  leather.  It  is  of  the  greatest  importance  to  those 
who  pursue  an  art  or  manufacture  that  they  be  acquainted 
with  such  modifications  of  the  ordinary  methods  of  work- 
ing as  may  be  likely  to  render  their  procedure  more  facile 
or  more  economical,  or  otherwise  tend  to  render  their 
manufacture  more  perfect  in  its  results.  With  this  view 
we  have  selected  from  the  lengthy  roll  of  patented  inven- 
tions certain  processes  which  we  hope  may  prove  in  some 
degree  interesting  and  useful.  While  refraining  from 
making  any  comments  upon  the  merits  of  any  of  these 
processes,  we  may  indulge  a  hope  that  from  some  of  them 
at  least  may  be  gleaned  a  fair  amount  of  useful  in- 
formation. 

The  First  English  Patents  for  Tanning.— As  speci- 
mens of  the  orthography  of  the  seventeenth  century,  the 
following  quaint  titles  of  specifications  may  prove  inte- 
resting. The  first  patent  for  improvement  in  leather  was 


170  LEATHER  MANUFACTURE. 

obtained  by  John  Jasper  Wolfen,  and  is  dated  December 
8th,  1627.  It  runs  as  follows : — 

"  A  newe  inveneon  for  the  making  and  pparing  of 
ctaine  stuffs  and  skynns  to  hould  out  wett  and  rayne." 

In  1635  Christopher  Hunt  obtained  a  patent  for  a 
"  Newe  invention  by  way  of  6  ymbrodering  or  hufling  of 
guilded  leather  upon  several  grounds  fitt  for  hangings  or 
other  furniture  for  houses/  ' 

In  1660,  Charles  Howard  patented  "A  newe  way  for 
the  tanning,  tawing,  dressing,  and  pparinge  all  sorts  of 
rawe  hydes  and  skinnes  into  leather  in  lesse  time  and  with 
lesse  charge  then  formerly  hath  bin  vsed." 

Newton's  Tanning  Process. — The  object  of  this  pro- 
cess is  to  hasten  the  operation  of  tanning  by  employing 
certain  earthy  or  metallic  salts  in  combination  with  vege- 
table astringent  matter,  by  the  joint  action  of  which  it  is 
said  the  combination  of  the  albuminous  matter  of  the 
skin  with  the  bases  is  promoted.  When  other  matter 
than  catechu  is  used,  the  latter,  of  good  quality  and  con- 
taining 50  per  cent,  of  tannin,  is  taken  as  a  standard  for 
regulating  the  proportion  of  the  former.  The  skins  must 
as  usual  be  tmhaired  and  free  from  lime.  For  treating 
100  calf-skins  the  following  formula  is  given  : — 

Alum 20  Ibs. 

Salt     10    „ 

Catechu 100    „ 

Sulphate  of  alumina    4    „ 

The  latter  salt  may  be  used  either  alone  or  mixed  with 
2  Ibs.  of  common  salt.  The  three  mixtures  are  dissolved 
in  water  in  separate  vessels,  and  kept  apart.  The  following 
directions  are  given  for  applying  the  various  solutions  : 
put  into  a  vat  one-fifth  of  the  first  solution,  one-tenth  of 
the  second,  and  one-fourth  of  the  third  ;  immerse  the 
skins  in  this  liquor,  handle  and  stir  them  repeatedly  for 
a  short  time,  then  take  them  out.  Now  refresh  the  vat 
by  the  addition  of  one-fifth  of  the  first  solution,  one- 
tenth  of  the  second,  and  one-fourth  of  the  third.  .Replace 
the  skins  in  this  mixture;  treat  as  before,  but  for  a  longer 


TANNING  PROCESSES.  *7i 

time.  Remove  the  skins  a  second  time,  refresh  the  vat 
with  one-fifth  of  the  first  solution,  one-tenth  of  the  second, 
replace  the  skins  in  the  vat,  and  allow  them  to  remain  for 
some  time,  handling  occasionally  as  before  ;  remove  them 
again,  and  mix  in  the  vat  the  residue  of  the  first  and 
third  solutions,  and  one-fifth  of  the  second.  Replace  the 
s'vins  in  the  vat,  and  a  few  days  after  take  them  out  and 
add  to  the  vat  the  remaining  two-fifths  of  the  second 
mixture.  Four  or  five  weeks  are  sufficient  to  complete 
the  tanning. 

The  above  process  may  be  modified  by  laying  the  skins 
in  a  vat  and  stratifying  them  with  3  Ibs.  of  moistened  tan. 
Other  skins  can  be  'thus  tanned,  but  the  proportions  must 
be  varied,  as  shown  below  :— 

For  100  goat  skins,  take — 

Alum    10  to  12  Ibs. 

Catechu 50  to  60    „ 

Salt 6  „ 

For  100  cow  hides,  take — 

Sulphate  of  alumina 40  to  50  Ibs. 

Salt   20  to  25    „ 

Catechu    500  „ 

For  ox  hides,  per  hide,  take — 

Sulphate  of  alumina 14  to  16  Ibs. 

Salt   8 

Catechu    60  to  70    „ 

Aldrich's  Process. — It  is  well  known  that  when  green 
hides  have  become  dry  the  surface  of  the  flesh  side  becomes 
hard  or  "  flinty,"  and  this  condition  is  a  source  of  much 
trouble  to  the  tanner,  and  necessitates  severe  mechanical 
treatment  to  render  the  hides  sufficiently  soft  to  undergo 
the  several  processes  which  convert  them  into  leather. 
Upon  this  subject  Dussauce  makes  the  following  observa- 
tions :  "  As  a  green  hide  becomes  dry,  by  evaporation  of 
its  liquid,  the  flesh  side  absorbs  oxygen  from  the  atmo- 
sphere, which,  combining  with  the  fresh  fibro-gelatinous 
surface,  forms  a  hard  flinty  scale.  To  free  the  hide  from 


17*  LEATHER  MANUFACTURE. 

the  scale,  and  facilitate  its  softening,  tanners  submit  it  to 
hard  beam  breaking,  or  to  the  action  of  a  hide-mill,  both 
of  which  have  the  detrimental  effect,  to  some  extent,  of 
disturbing  the  uniform  relations  of  the  interposed  gelatine, 
and  loosening  the  small  bundles  of  fibres  composing  the 
structure  of  the  hide,  thereby  weakening  the  hide  in  its 
textile  strength ;  nor  have  any  of  the  modern  soaks  proved 
less  detrimental,  depending  as  they  do  upon  a  putrefactive 
condition  (sweating).  The  first  effect  of  such  soak  is  to 
decompose  the  parts  of  the  hides  easiest  effected,  generally 
the  fibro- gelatinous  structure  immediately  beneath  the 
scale  ;  hence  the  frequent  water  peltings  and  running  of 
hides  in  the  soak,  particularly  in  warm  weather." 

As  a  substitute  for  the  ordinary  mechanical  treatment 
and  soakings,  which  are  thus  so  clearly  shown  by  Dussauce 
to  be  mischievous  to  the  structure  of  the  hides,  Mr. 
Aldrich,  of  St.  Louis,  U.S.A.,  devised  a  chemical  process 
by  which  it  is  said  the  hides  may  be  rendered  as  soft  and 
pliant  as  when  first  removed  from  the  animal. 

Aldrich's  process  for  the  treatment  of  dry  flint  hides  is 
thus  given : — 

The  hides  are  first  soaked  in  clear  water  until  pliant ; 
they  are  then  placed  in  an  acid  bath  composed  as  follows  : — 

Acetic  acid 1  part. 

Water 16  parts. 

In  from  24  to  36  hours  the  above  solution  will  dissolve  the 
scale,  by  combining  with  its  oxygen,  and  swell  the  fibres  of 
the  hides,  when  they  are  to  be  immersed  in  the  following 
bath  :— 

Carbonate  of  ammonia 1  part. 

Water 70  parts. 

This  solution,  having  a  strong  affinity  for  the  acid 
absorbed  by  the  hide  from  the  first  bath,  saturates  it  in 
from  48  to  72  hours,  leaving  the  hide  in  a  naturally  pliant 
and  soft  condition,  and  so  perfectly  transformed  from  a  dry 
to  a  green  condition  that  no  tanner  can  detect  the  slightest 
difference  between  stock  tanned  from  dry  hides  so  prepared 


TANNING  PROCESSES.  »73 

from  the  green  hides.  The  first  cost  of  the  acid  solution 
is  two  cents  per  gallon,  or  twenty  dollars  for  a  large  pool 
full,  after  which  it  can  be  used  continually,  attended  with 
no  expense  except  pumping  up  and  passing  it  through 
the  apparatus  to  renew  its  strength  after  it  has  been  used. 
The  second  solution  is  prepared  from  all  bate  water,  and 
is  attended  with  no  expense  but  pumping. 

The  above  process  is  said  to  obviate  all  danger  of  damage 
from  taint  or  running,  for  its  action  is  so  perfectly  anti- 
septic that  hides  so  softened  may  be  kept  for  weeks  in 
water  before  being  placed  in  lime;  also  by  keeping  fibrous 
and  flanky  hides  in  the  first  bath  double  the  ordinary  time, 
they  will  plump  up  and  be  materially  improved,  and  all 
without  any  breaking  whatever. 

Orgereau's  Process. — The  object  of  this  process  is  to 
shorten  the  time  usually  occupied  by  the  tanning  process, 
and  which  is  effected  by  a  systematic  arrangement  of  the 
materials  employed.  The  skins  are  submitted  to  the 
usual  operations  of  depilation  and  raising,  and  are  then 
placed,  in  alternate  layers  of  tan  and  skin,  in  a  vat  with  a 
perforated  false  bottom.  This  vat  being  about  three- 
fourths  full,  is  drenched  with  water  for  the  first  operation, 
and  with  weak  tan  liquor  for  the  succeeding  operations. 
The  liquid  slowly  penetrates  into  the  mass,  and  after 
having  moistened  the  contents  of  the  vat,  runs  through 
the  false  bottom  into  a  reservoir,  from  which  it  is  conveyed 
back  to  the  surface  of  the  materials.  The  inventor  em- 
ploys six  vats,  each  containing  100  native  or  120  imported 
hides.  The  liquid  passing  into  the  reservoir  is  daily  dis- 
tributed over  the  surface  of  the  materials  in  the  vat  by 
means  of  a  pump.  This  operation  is  continued  for  one 
month,  at  the  end  of  which  time  the  vat  is  emptied  and 
the  spent  bark  replaced  by  fresh  bark,  and  the  same  pro- 
cess of  infiltration  repeated.  A  third  operation  is  neces- 
sary to  obtain  a  proper  tanning.  The  entire  process 
occupies  four  months,  and  the  leather  produced  is  stated 
to  be  equal  in  quality  to  that  obtained  by  the  old  method  ; 
100  parts  of  dry  Buenos  Ayres  hides  yield,  by  the  above 
process,  150  parts  of  leather.  It  may  be  mentioned  that 


174  LEATHER  MANUFACTURE. 

the  inventor  of  the  above  process  is  an  eminent  Parisian 
tanner. 

Jennings's  Process. — In  applying  this  process  to  thick 
ox  hides,  they  are  first  unhaired  in  the  usual  manner, 
either  by  steeping  them  in  a  lime  bath,  or  by  the  more  recent 
process  of  siceating.  If  lime  has  been  used,  the  hides  are 
steeped  in  dilute  hydrochloric  acid  after  they  have  been 
dehaired,  and  then  washed.  This  operation  proves  and 
fits  them  for  the  succeeding  operations.  They  are  now 
piled  in  batches  of  a  dozen  hides  each,  with  a  hurdle  or 
wicker  between  each  pair ;  they  are  then  alternately 
lowered  into  tanks  filled  with  the  following  solution  : — 

Tank  JSTo.  1  is  charged  with  a  strong  solution  of  alum, 
to  which  10  per  cent,  each  of  sulphuric  and  hydrochloric 
acids  are  added. 

Tank  No.  2  is  charged  with  a  concentrated  solution  of 
soda  ash,  to  which  is  added  5  per  cent,  of  tungstate  of 
soda.  The  skins  or  hides  are  immersed  six  hours  at  a 
time  in  these  tanks,  then  withdrawn  and  drained,  and 
transferred  alternately  from  the  first  to  the  second  tank, 
and  vice  versa,  until  the  hide  is  sufficiently  hardened. 
The  condition  of  the  hide  is  known  by  cutting  a  small 
piece  off  with  a  knife.  At  this  stage  they  are  immersed 
for  six  hours  in  a  strong  solution  of  tungstate  of  soda 
alone,  then  lifted,  drained,  and  placed  in  a  liquor  of  soap, 
made  by  dissolving  20  Ibs.  of  soap  in  every  10  gallons  of 
water,  and  the  hides  agitated  in  this  until  the  strength 
of  the  soap  is  exhausted  by  being  absorbed  by  the 
hide.  They  are  now  washed  in  soft  water,  and  finally 
steeped  for  twenty- four  hours  in  a  common  liquor  of  oak- 
bark,  after  which  they  are  dried  and  finished  in  the  usual 
manner. 

Ballatschano  and  Trenk's  Process. — This  is  one  of 
the  numerous  quick  processes,  and  is  thus  briefly  described: 
In  the  treatment  of  horse  hides,  more  especially,  by  this 
process  a  considerable  increase  in  substance  is  said  to  be 
obtained.  The  hides  are  treated  with  the  following  tan- 
ning compounds,  either  singly,  or  in  a  certain  order,  or 
mixed  together  according  to  the  kind  of  hide,  its  thick- 


TANNING  PROCESSES.  175 

ness,  and  the  various  purposes  to  which  it  is  to  be  applied. 
The  compounds  employed  are  :  1.  A  solution  of  chromate 
of  alumina  in  pyroligneous  acid  (wood  vinegar)  in  the 
proportions  of  about  1000  parts  of  water  to  20  or  30  parts 
respectively  of  the  chromate  and  acid.  2.  A  concentrated 
solution  of  argol,*  to  which  is  added  a  small  quantity  of  a 
protoxide  (such  as  nickel)  in  ammonia.  The  argol  bath 
is  said  to  have  the  property  of  considerably  increasing 
the  substance  of  the  hides  after  treatment  in  the  bath 
of  pyroligneous  acid  and  chromate  of  alumina,  if  the 
hides,  after  being  removed  from  this  bath  and  rinsed,  are 
treated,  while  still  wet,  with  the  solution  for  twenty-four 
to  forty-eight  hours,  or  longer.  The  patentees  state  that 
the  hides  treated  with  the  argol  bath  "  are  rendered  so 
sensitive  to  vegetable  tanning  agents  that  a  bath  of  1 
part  tannin  in  1000  parts  of  water  and  20  parts  of  pyro- 
ligneous acid  will  tan  a  hide  in  thirty  days,  whereas  a 
hide  not  treated  with  the  argol  bath  will,  with  the  excep- 
tion of  the  brown  colouring,  show  no  trace  of  tanning 
under  the  same  treatment."  Tanning  with  the  above 
ingredients  may  be  effected  in  various  ways.  Thus,  if  2 
parts  of  solution  No.  1  are  mixed  with  1  part  of  solution 
No.  2,  the  tanning  of  thick  ox  and  horse  hides  can 
be  completely  effected  in  the  mixture  in  from  eighteen 
to  twenty-one  days.  When  possible  to  maintain  the 
bath  at  a  constant  temperature  of  from  72°  to  82°  Fahr., 
the  tanning  can  be  more  quickly  effected.  The  raw 
hides  to  be  tanned  by  this  process  are  to  be  prepared  in 
the  usual  way. 

According  to  the  purpose  to  which  the  finished  leather 
is  to  be  applied,  different  mixtures  of  both  solutions,  1 
and  2,  are  employed.  For  example  : — a,  2  parts  solution 
No.  1  and  1  part  solution  No.  2  ;  b,  the  hides  are  first 
treated  with  solution  No.  1,  and  then  for  any  desired 
length  of  time  with  solution  No.  2  ;  c,  the  hides  are 
merely  treated  with  solution  No.  1.  A  small  quantity  of 
carbolic  acid  is  recommended  to  be  added  to  the  baths. 
The  hides  treated  by  the  above  process  must  afterwards 
*  Crude  bitartrate  of  potash,  as  deposited  by  wine. 


«76  LEATHER  MANUFACTURE. 

be  carefully  washed  and  then  finished  in  the  usual  way. 
Before  tanning,  the  hides  must  be  completely  freed  from 
lime. 

Lomas's  Process.  —  This  process  consists  in  tanning 
with  valonia,  American  pearlash,  and  oak-bark.  For 
ordinary  hides  and  skins  four  baths  are  used.  The  first 
bath  is  composed  of  a  solution  of  valonia  marking  about 
1°  on  Twaddell's  hydrometer,  and  about  4  Ibs.  of 
American  pearlash  in  160  gallons  of  the  solution.  In  this 
bath  the  hides  remain  about  three  days.  The  second  bath 
is  composed  of  valonia  solution  marking  3°  Tw.,  and  of 
pearlash  in  the  proportion  of  5  Ibs.  to  150  gallons.  The 
hides  remain  in  this  bath  four  days.  The  third  bath  is 
composed  of  valonia  solution  at  7°  Tw.,  and  pearlash  in 
the  proportion  of  5J  Ibs.  to  150  gallons,  in  which  the 
hides  are  immersed  for  seven  days.  The  fourth  or  final 
bath  is  composed  of  solution  at  2°  Tw.,  and  pearlash  2  J 
Ibs.  to  150  gallons.  Between  each  hide  or  skin,  as  they 
are  placed  in  the  bath,  about  6  Ibs.  of  oak-bark  or  valonia 
are  spread,  and  in  this  bath  they  remain  fourteen  days. 
For  very  thick  hides  the  first  two  baths  are  the  same  "as 
for  ordinary  hides  ;  they  are  afterwards  placed  in  a  bath 
composed  of  valonia  solution  at  9°  Tw.,  and  2J  Ibs.  of 
pearlash  to  150  gallons  of  solution,  in  which  they  remain 
nine  days.  They  are  afterwards  placed  in  a  final  bath, 
similar  to  that  used  for  the  other  hides,  for  fourteen  days. 
Instead  of  valonia,  oak-bark  or  other  equivalent  tanning 
material  may  be  used.  The  hides  are  handled  in  all  but 
the  last  bath. 

Michel,  Kollen,  and  Hertzog's  Process. — The  object 
of  this  process  is  to  ensure  rapid  tanning,  by  which  calf 
skins  may  be  tanned  in  a  few  hours,  and  cow  or  ox  hides 
in  about  forty-eight,  while  at  the  same  time  the  leather 
produced  possesses  all  the  flexibility  and  firmness  indis- 
pensable to  a  perfect  product. 

To  carry  out  the  invention  a  set  of  apparatus  is  employed, 
the  essential  objects  of  which  are,  first,  to  regulate  at  will 
during  the  operation  of  tanning  the  temperature  of  the 
liquors  in  the  operating  tank  and  in  the  receptacle  con- 


TANNING  PROCESSES.  177 

taining  the  hides  to  be  tanned ;  second,  to  regulate  the 
density  of  the  liquors  in  the  said  receptacle  and  also  to 
change  their  nature  as  required  for  consecutive  processes 
without  interrupting  the  operation  of  the  apparatus ;  third, 
the  clarifying  of  the  liquors  used  in  former  processes,  in 
order  to  enable  them  to  serve  for  future  purposes ;  and  it 
is  by  the  combination  of  these  means  that,  according  to  the 
present  invention,  rapid  tanning  may  be  effected.  For 
these  purposes  the  skins  or  hides  are  introduced  into  a 
drum  revolving  on  horizontal  trunnions,  one  of  which  is 
hollow,  to  admit  of  the  passage  of  a  suction-pipe  leading 
from  a  pump,  and  a  delivery-pipe  leading  from  a  raised 
liquor  tank,  both  of  which  pipes  descend  in  the  drum 
within  a  partition  thereof,  so  as  to  draw  the  liquor  there- 
from and  discharge  it  into  the  same  at  or  near  its  lowest 
point.  From  the  pump  a  delivery-pipe  passes  up  into 
the  tank,  so  that  by  the  pump  the  liquor  can  be  with- 
drawn from  the  drum  while  this  continues  to  revolve,  and 
can  be  discharged  into  the  tank,  it  being  made  to  pass 
through  a  refrigerating  apparatus  on  its  way,  while  from 
the  tank  the  same  liquor  may  either  be  discharged  back 
into  the  drum,  after  having  been  raised  to  any  desired 
temperature  by  means  of  a  worm  heated  by  steam  or  hot 
water,  or  the  liquor  may  be  passed  from  the  tank  througli 
the  pipes  into  one  or  more  niters  in  order  to  be  clarified, 
the  discharged  clarified  liquor  being  collected  in  other 
tanks,  whence  it  can  be  drawn  by  the  pump  and  discharged 
into  the  first-named  tank  again. 

By  these  means,  it  will  be  seen  that  while  the  skins  or 
hides  are  being  continuously  subjected  to  the  action  of  the 
rotating  drum,  the  liquor  may  at  the  same  time  be  continu- 
ously made  to  circulate  from  the  drum  through  the  pump, 
refrigerator,  and  main  tank  back  to  the  drum,  whereby  a 
constant  definite  temperature  of  the  liquor  may  be  main- 
tained during  the  tanning  operation,  the  action  of  the 
refrigerator  and  of  the  heating- worm  in  the  tank  being 
regulated  to  any  required  degree.  Or  during  the  operation 
the  liquor  may  be  continuously,  or  periodically,  clarified 
by  causing  it  to  pass  from  the  main  tank  to  the  filters 

H 


178  LEATHER  MANUFACTURE. 

and  thence  back  to  the  pump,  as  described.  Or  again, 
where  the  hides  have  to  be  subjected  consecutively  to  a 
series  of  different  operations,  requiring  different  descrip- 
tions of  liquors,  these  may  also  be  all  effected  in  one 
and  the  same  drum  by  withdrawing  the  liquors  there- 
from by  the  pump  at  the  end  of  each  particular  opera- 
tion, and  supplying  the  liquor  required  for  the  next 
operation  from  other  tanks,  which  also  communicate  with 
the  pump  by  pipes.  The  delivery-pipe  of  the  pump  also 
has  a  branch  provided  with  a  stopcock  leading  to  a  dis- 
charge drain,  so  that  any  particular  liquor  that  has  been 
employed  in  the  drum  and  that  is  of  no  further  use,  can 
be  withdrawn  by  the  pump  and  discharged  to  waste, 
instead  of  being  conveyed  into  the  main  tank  again. 

The  apparatus  is  thus  described : — "  Fig.  24  is  a  longi- 
tudinal section,  partly  in  elevation,  and  Fig.  25  is  a  plan. 
A  is  a  wooden  drum  mounted  to  revolve  on  a  horizontal 
axis,  having  at  each  side  trunnions  that  work  in  suitable 
bearings.  On  the  one  trunnion  is  fixed  a  worm  wheel,  A1, 
gearing  with  a  worm  driven  by  any  suitable  motor,  causing 
the  drum  A  to  revolve  slowly — that  is  to  say,  to  make  from 
ten  to  fifteen  revolutions  per  minute,  according  to  the 
nature  of  the  hides  operated  on.  The  other  trunnion  is 
tubular,  and  through  it  pass  freely  two  pipes,  a  and  b, 
which  are  supported  by  an  external  bracket.  The  one 
pipe,  a,  bends  downwards  within  the  drum  nearly  to  its 
inner  periphery.  A  partition,  p,  having  perforations 
through  it,  separates  the  body  of  the  drum  from  the  end 
space  which  the  pipes  a  and  b  enter.  A  manhole,  D, 
which  can  be  tightly  closed  by  a  cover,  serves  to  admit 
into  the  drum  the  hides  to  be  operated  on  and  to  remove 
them.  The  drum  has  inwardly  projecting  ribs  or  studs, 
A2,  which  assist  in  agitating  the  hides  as  the  drum  revolves. 
B  is  a  pump  having  its  suction  communicating  with  the 
pipe,  a,  and  its  discharge  communicating  by  a  pipe,  d,  with 
the  top  of  a  service  tank,  E.  In  the  course  of  the  pipe,  dt 
there  is  interposed  a  refrigerator,  r,  consisting  of  a  sheaf 
of  tubes  within  a  casing  supplied  with  cold  water  or  brine 
that  is  cooled  by  a  refrigerating  apparatus,  which  is  caused 


TANNING  PROCESSES. 


179 


to  circulate  through  it  while  the  liquid  conducted  by  the 
pipe,  d,  flows  through  the  tubes. 

"  The  service  tank,  E,  is  placed  at  a  high  level  on  a 
platform   supported   by   columns,   so  that   there  is  free 


Ffc.  25. 


space  under  it.  The  top  of  the  tank  has  an  opening, 
in  which  is  suspended  a  wicker  basket,  El,  which  serves 
to  retain  solid  matters  discharged  along  with  the  liquid 
from  the  pipe  d.  At  the  bottom  of  the  tank,  E,  is 
placed  a  serpentine  pipe,  kt  through  which  steam  or  hot 


i8o  LEATHER  MANUFACTURE. 

water  can  be  passed  when  required  to  heat  the  contents  of 
the  tank.  From  the  bottom  of  the  tank  the  pipe  b,  pro- 
vided with  a  stopcock,  leads  to  the  interior  of  the  drum  A. 
At  the  side  of  the  tank  is  placed  a  thermometer,  H,  to 
indicate  the  temperature  of  the  liquid  in  the  tank.  1 1  are 
niters,  having  within  them  perforated  removable  trays 
made  of  copper,  on  which  are  placed  filtering  materials, 
such  as  small  pebbles,  0,  or  a  mixture  of  charcoal  and 
Spanish  white,  pl,  to  purify  and  clarify  liquid  conducted 
from  the  tank  E  to  the  filters  J  j,  from  which  it  is  pumped 
back  by  the  pump  B,  communicating  with  the  tanks  by  a 
pipe,  n.  Other  tanks,  K  and  L,  are  provided  to  contain  a 
reserve  of  liquid  and  to  allow  of  subsidence,  these  reserve 
tanks  being  connected  by  supply  pipes  with  the  service 
tank  E,  and  having  branch  pipes,  rt  connected  to  the  suction- 
pipe,  n,  of  the  pump  B.  The  branch-pipes  to  and  from  the 
several  tanks  are  provided  with  suitable  stopcocks,  so  that 
they  can  be  charged  or  emptied  as  required. 

"By means  of  the  apparatus  arranged  as  above  described, 
the  drum  A,  while  it  revolves,  can  be  charged  to  any  desired 
9xtent  with  tanning  liquid  supplied  by  the  pipe  b  from  the 
tank  E,  and  whilst  liquid  is  so  supplied  liquid  can  be  with- 
drawn by  the  pipe  a  and  pump  B  from  the  lower  part  of  the 
drum,  and  returned  to  the  tank  E  cooled,  if  necessary,  on 
its  passage  through  the  refrigerator  F,  or  heated,  if  required, 
by  the  serpentine  k;  thus  the  same  liquid  can  be  continu- 
ously circulated  through  the  revolving  drum  with  its  tem- 
perature and  quantity  varied  as  required.  Moreover,  by 
causing  the  pump  B  to  draw  from  one  or  other  of  the 
reserve  tanks  J,  K,  or  L,  the  strength  and  quality  of  the 
liquid  can.  be  varied,  while  still  its  temperature  can  be 
regulated  as  above  described.  It  is  by  a  suitable  regulation 
of  the  temperature,  strength,  and  quality  of  the  tanning 
liquid  that  acts  in  the  drum  A  on  the  skins  or  hides  which 
are  kept  in  movement  by  its  rotation,  with  suitable  varia- 
tions of  these  conditions  at  the  successive  stages  of  the 
tanning  process,  that  we  are  enabled  to  effect  rapidly  and 
completely  the  conversion  into  leather  of  high  quality. 
In  order  that  the  nature  of  the  operation  may  be  better 


TANNING  PROCESSES.  iSi 

understood,  we  will,  by  way  of  example,  describe  its 
application  to  the  two  ordinary  processes,  so  as  to  guide 
a  practical  tanner  to  its  application  in  these  and  in  other 
cases. 

"I.  Tanning  Process  for  Soft  Leather. — For  calf  and 
other  soft  skins  the  drum  is  charged  with  about  560  gallons 
of  tanning  liquor  of  ordinary  composition,  the  tanning 
extracts  which  it  contains  being  selected  to  suit  the  colour 
to  be  given  to  the  leather.  The  density  of  the  liquor  should 
be  from  30°  to  35°  of  the  tanning  density  gauge  [barko- 
meter],  and  its  temperature  50°  to  60°  Fahrenheit.  The 
skins  to  be  treated  with  this  quantity  of  liquor  may  weigh 
from  1,400  Ibs.  to  1,550  Ibs.,  and  these  are  introduced 
into  the  drum  in  their  soft,  hairless  condition,  along  with 
soleine  (essence  of  distilled  turpentine),  in  the  propor- 
tion of  about  3J  pints  of  soleine  to  every  220  Ibs.  of 
skins.  The  drum  thus  charged  is  caused  to  revolve  at 
a  circumferential  speed  of  from  400  feet  to  410  feet  per 
minute.  In  consequence  of  the  '  fermentation  '  or  action 
resulting,  the  temperature  rises  to  65°  or  70°  Fahr.,  at 
which  it  is  maintained  for  four  or  five  hours.  It  is  then 
allowed  to  rise  gradually  to  about  85°  during  a  period  of 
twelve  to  fourteen  hours,  at  the  end  of  which  time  the 
tanning  is  complete. 

"  II.  Tanning  Process  for  Hard  Leather. — The  process  is 
similarly  conducted,  but  extended  over  a  longer  period, 
according  to  the  thickness  of  the  leather,  and  with  liquor 
strengthened  by  addition  of  about  5  Ibs.  of  divi  divi  to 
every  100  Ibs.  of  hides  treated,  or  equivalent  addition  of 
other  tanning  material.  For  cow  hide,  for  instance,  the 
duration  should  be  about  48  hours,  the  final  temperature 
being  allowed  to  rise  to  nearly  100°  Fahr.  At  the  end  of 
the  tanning  operation  the  drum  is  almost  emptied  of  liquor, 
and  the  hides  are  subjected  for  about  fifteen  or  twenty 
minutes  to  the  beating  action  of  the  revolving  drum,  after 
which  fresh  and  very  strong  tanning  liquor  is  gradually 
introduced  into  the  drum,  which  is  then  kept  revolving 
for  about  two  hours.  This  has  the  effect  of  rendering  the 
leather  firm.  The  hides  when  tanned,  whether  for  hard 


1 82  LEATHER  MANUFACTURE. 

or  soft  leather,  when  removed  from  the  drum  are  soaked 
for  several  hours  in  a  weak  liquor  at  the  temperature  of 
the  atmosphere.  The  liquors  discharged  from  the  drum 
are  filtered  and  clarified,  and  restored  to  the  required 
strength  for  a  succeeding  operation." 

Keasley's  Process. — This  consists  in  the  construction 
and  employment  of  certain  apparatus,  whereby  the  opera- 
tion of  tanning  hides  may  be  more  conveniently,  advan- 
tageously, and  effectually  carried  on  than  upon  the 
ordinary  plan.  It  is  well  known  to  all  tanners  that  the 
quality  and  weight  of  leather  is  much  improved  and 
increased  by  occasionally  removing  the  hides  or  skins  from 
the  liquor,  and  exposing  them  for  a  short  time  to  the  action 
of  the  atmosphere.  The  ordinary  plan  of  doing  this  is 
by  pulling  the  hides  or  skins  one  by  one  out  of  the  pit 
by  manual  labour,  with  the  assistance  of  a  hooked  instru- 
ment. This  operation  takes  considerable  time,  and  when 
the  hides  are  large  is  a  very  laborious  occupation. 

By  this  invention  a  machine  or  apparatus  is  employed 
by  which  a  much  better  result  may  be  arrived  at,  and  at 
the  same  time  the  operation  may  be  shortened,  the  labour 
considerably  diminished,  and  the  weight  of  the  leather 
increased.  The  apparatus  consists  of  a  square,  rectangular, 
or  other  conveniently  shaped  frame,  from  which  the  hides 
or  skins  are  suspended  vertically  in  any  convenient 
manner.  The  dimensions  of  the  framing  from  which  the 
hides  are  suspended  must  of  course  correspond  with  the 
size  of  the  pit,  so  that  the  frame  belonging  to  each  pit, 
and  with  it  the  hides,  may  be  raised  or  lowered  at  the 
discretion  of  the  workmen.  Each  of  these  frames  con- 
taining the  hides  is  distinct  and  separate,  and  may  be 
raised  and  lowered  separately  by  manual  labour,  with  the 
assistance  of  a  windlass  if  required;  but  it  is  found 
advisable  to  connect  two  contiguous  frames  together,  so 
as  to  make  them  counterbalance  each  other,  and  thus 
considerably  diminish  the  labour  of  working  them.  A 
variety  of  means  may  be  devised  for  carrying  this  idea 
into  effect,  but  those  shown  in  the  accompanying  draw- 
ings will  be  found  fully  to  answer  the  purpose. 


TANNING  PROCESSES. 


183 


Fig.  26  represents  a  side  elevation,  and  Fig.  27  an  end 
elevation  of  one  plan,  in  which  the  frames  a  a  a  a,  filled 


Fig.  26. 

with  hides  or  skins  b  b,  are  suspended  from  the  extremi- 
ties of  a  vibrating  beam  or  lever  c  c,  by  means  of  chains 


1*4 


LEATHER  MANUFACTURE. 


or  cords  d  d.     The  tan-pits   or  vats  e  e  are    shown   in 
section  in  both  these  figures.    The  beam  or  lever  c  c  is 

mounted  at  /  in  bearings 
firmly  fixed  in  the  framing, 
g  g,  for  that  purpose,  and  is 
worked  up  and  down  by 
means  of  chains  or  cords,  h  h, 
which  pass  round  a  windlass 
or  barrel  i  i,  below,  and  are 
fastened  at  either  end  to  the 
extremities  of  the  vibrating 
beam.  On  the  axle  of  the 
windlass  is  mounted  a 
toothed  wheel/,  seen  by  dots 
in  Fig.  28,  and  is  driven  by 
a  pinion  k,  which  is  fixe'd 
on  the  shaft  I,  and  is  actu- 
ated by  applying  power  to 
the  shaft  by  means  of  a 
winch  or  otherwise.  It  will 
now  be  understood  that  as 
the  pinion  k,  toothed  wheel/, 
and  barrel  or  windlass  i  i, 
are  made  to  revolve,  that  one 
end  of  the  beam  or  lever  c  c 
will  be  raised  and  the  oppo- 
site end  depressed  by  one  of 
the  ropes  passing  over  and 
the  other  under  the  barrel, 
and  by  this  means  one  frame 
of  hides  will  be  lifted  out  of 
the  tan  liquor  while  the 
hides  on  the  opposite  one 
are  totally  immersed.  This 
operation  may  be  reversed 
lg*  by  merely  turning  the  winch 

in  the  opposite  direction.  The  ascent  and  descent  of  the 
frames  is  assisted  by  the  forked  guides  m  m  (see  Fig.  27), 
which  work  against  the  vertical  guide-rods  n  n.  At 


TANNING  PROCESSES. 


185 


night  or  at  other  times  when  it  is  necessary  that  the 
hides  on  both  frames  should  be  immersed,  this  object 
is  easily  effected  by  unhooking  from  the  suspending 
chains  d  d,  by  means  of  the  hook  r,  the  frame  that  is 
already  immersed,  and  then  allowing  the  other  frame  to 


Fig.  28. 

descend  into  the  liquor,  which  it  will  easily  do  by  its  own 
weight.  When  one  of  the  frames  is  raised,  it  is  kept 
elevated  by  merely  placing  a  leathern  or  wooden  block 
between  the  teeth  of  the  toothed  wheel  j  and  pinion  k, 
and  thereby  preventing  them  from  revolving.  This  stop 


1 86 


LEATHER  MANUFACTURE. 


fully  answers  the  purpose,  and  is  found  more  convenient 
than  a  pawl  and  ratchet-wheel. 

Fig.  28  represents  a  side  elevation  of  another  plan  of 
carrying  out  the  counterbalance  principle.     In  this  plan 


Fig.  29. 


the  vibrating  beam  c  c  is  suppressed,  and  the  suspending 
chains  d  d,  and  the  working  chains  h  h,  are  united  together, 
and  form  the  chains  o  o,  which  pass  over  pulleys  p  p  at  the 
outer  extremities  of  the  standards  g  g,  and  down  between 


TANNING  PROCESSES.  187 

the  two  other  pulleys  q  q,  and  wind  the  barrel  or  wind- 
lass i  i,  as  in  the  former  instance.  If,  however,  it  is 
thought  more  desirable,  the  pulleys  p  p  and  q  q  may  be 
attached  to  a  beam,  or  the  ceiling  above,  instead  of  to  the 
standards  g  g.  The  barrel  i  is  furnished  with  a  toothed 
wheel  /,  and  is  driven  by  a  pinion  k,  precisely  in  the 
manner  already  explained  in  reference  to  Figs.  27  and  28. 

In  Fig.  29  is  shown  a  means  of  raising  the  frames  con- 
taining the  hides  one  at  a  time.  In  this  case  the  pulleys 
are  fastened  as  before  mentioned  to  a  beam  above,  the 
windlass  or  barrel  being  placed  below. 

Fig.  30  represents  another  plan  of  raising  the  frames. 
In  this  instance  several  frames,  with  the  hides  or  skins 
suspended  vertically,  may  be  raised  at  one  time,  but  not 
upon  the  counterbalance  principle.  The  frames  with  the 
hides  are  raised  by  means  of  a  rope  ssss,  which  passes 
over  pulleys  tttt,  affixed  to  a  strong  beam  u  u  u  above. 
One  end  of  the  rope  s  s  is  firmly  fixed  to  the  beam,  as  seen 
in  the  drawing,  and  the  other  end  is  passed  over  the  pulleys 
1 1,  and  round  a  windlass  at  the  other  extremity  of  the 
beam.  The  suspension  cords  of  the  frames  are  furnished 
with  a  pulley  v  v,  constructed  in  such  a  manner  that  it  may 
with  facility  be  hooked  on  to,  or  detached  from,  the  rope 
ss,  according  to  whether  it  be  required  to  raise  the  frames 
containing  the  skins  out  of  the  tan  liquor  or  to  allow  them 
to  remain  immersed.  It  will  be  found  most  convenient  to 
raise  only  one-half  the  number  of  frames  at  one  time, 
leaving  the  remainder  in  the  tan  liquor.  In  order  to  do 
this  the  rope  s  s  is  brought  down  to  every  other  frame, 
and  the  pulleys  v  v  hooked  on  to  the  rope ;  then  by  turning 
the  windlass  and  causing  the  rope  s  s  to  become  poiled 
thereon,  the  frames,  with  the  hides  suspended  therefrom, 
will  be  raised  out  of  the  pits,  the  other  frames  which  are 
not  attached  to  the  ropes  remaining  immersed.  When 
the  first  lot  of  skins  have  been  exposed  for  a  sufficient 
length  of  time  to  the  atmosphere,  the  frames  are  lowered 
into  the  liquor  again,  where  they  are  allowed  to  remain 
by  unhooking  the  pulleys  v  v,  which  connect  them  to  the 
rope  8  8,  and  those  which  were  before  immersed  are 


i88 


LEATHER  MANUFACTURE. 


now  to  be  raised  by  hooking 
them  in  their  turn  by  means 
of  their  pulleys  v  V  on  to  the 
rope  s  s.  If  thought  desir- 
able the  counterbalance  prin- 
ciple may  be  applied  to  this 
arrangement  of  raising  and 
lowering  the  frames  by 
merely  employing  an  addi- 
tional rope,  s  s,  passed  over 
pulleys,  exactly  similar  to 
the  one  shown  in  the  draw- 
ing. One  end  of  this  rope 
also  would  be  firmly  attached 
to  the  end  of  the  beam  u  M, 
and  the  opposite  end  to  the 
windlass  or  barrel ;  or  in- 
stead of  two  ropes,  one  only 
may  be  employed  by  having 
it  of  sufficient  length  to 
pass  from  the  end  of  the 
beam  over  the  pulleys,  round 
the  windlass,  back  again  over 
similar  pulleys  to  the  end  of 
the  beam,  so  as  to  present  a 
double  rope,  to  one  part  of 
which  the  three  frames  1,  3, 
5,  would  be  suspended, 
while  the  other  frames,  2, 
4,  6,  would  be  suspended 
from  the  other  rope.  Now, 
if  a  double  rope,  s,  is  em- 
ployed there  will  be  no  ne- 
cessity to  detach  the  frames 
from  the  ropes  ;  the  pulleys 
v  v  are  merely  made  to  run 
freely  on  the  ropes,  and  are 
not  required  to  be  construc- 
ted so  as  to  hook  on  as  before 


TANNING  PROCESSES. 


189 


mentioned.  It  will  now  be  understood  that  if  the  counter- 
balance principle  is  carried  out  in  this  manner,  one  set  of 
frames  will  be  elevated  while  the  others  are  immersed,  arid 


the  action  of  lowering  one  set  will  raise  the  other  ;  that  is, 
when  the  windlass  is  unwinding  the  rope  to  lower  one  set, 
it  is  at  the  same  time  winding  up  the  other  rope,  and 
thereby  raising  those  frames  connected  with  it. 


'9°  LEATHER  MANUFACTURE. 

Fig.  31  represents  another  plan  of  raising  the  frames. 
In  this  plan  a  travelling  windlass  is  used,  which  may  be 
made  to  travel  along  a  railway  or  floor  constructed  on  the 
top  of  the  beam  above  the  frames.  When  it  is  required 
to  raise  a  frame  with  its  skins  or  hides,  the  windlass  is 
moved  along  the  railway  or  floor  to  immediately  above 
the  frame ;  then  a  rope  with  a  hook  at  the  end  is  let  down 
to  the  frame,  which  is  then  attached  thereto.  The  frame 
is  then  raised  up  by  means  of  the  windlass  until  the  skins 
are  drawn  out  of  the  liquid  and  are  completely  exposed  to 
the  atmosphere ;  the  frame  is  then  suspended  from  a  hook, 
firmly  fastened  to  the  beam,  where  it  remains  until  the 
manufacturer  thinks  it  advisable  ,to  immerse  the  hides  or 
skins.  Again  having  raised  one  frame  up  and  suspended  it 
from  the  hook,  the  attendant  releases  the  rope  belonging  to 
the  windlass,  and  proceeds  along  the  floor  or  railway  with 
the  windlass  to  another  frame,  which  he  raises  and  sus- 
pends from  its  hook  in  the  same  way.  When  it  is  required 
to  lower  the  frames  and  their  hides  into  the  liquor,  this 
must  be  done  by  means  of  the  windla?s  in  exactly  the 
same  manner. 


CHAPTER  XIV. 

TANNING  PROCESSES.— Continued. 

Page's  Process. — Casimir  Be%  and  Sons'  Process.— Snyder's  Process. — 
De  Bock's  Process. — Funcke's  Process. — Hamer's  Process.— Cox's 
Process.  —  Nossiter's  Process. — Desmond's  Process.  —  Burbidge's 
Process.— Kleman's  Process. 

Page's  Process. — By  this  process  the  hides  and  skins 
are  limed  in  weak  and  strong  solutions,  unhaired 
"drenched"  in  hen  manure  or  other  suitable  bate,  and 
immersed  and  handled  in  colouring  liquors  made  from 
equal  parts  of  any  suitable  bark  and  sweet  fern,  cutch 
and  sweet  fern,  or  gambier  and  sweet  fern.  A  mixture  is 
then  prepared  with  the  following  ingredients :  40  parts 
of  common  salt,  chloride  of  potassium,  or  ammonium,  40 
parts  of  alum,  and  13  parts  of  saltpetre.  These  ingredients 
are  thoroughly  mixed  and  dissolved  in  four  vats  half  filled 
with  water.  The  vats  measure  6  feet  by  4,  and  are  num- 
bered 1,  2,  3,  and  4.  One-third  more  of  the  mixture  is  put 
in  3  and  4  than  in  1  and  2  vats.  After  a  "  salt  solution  " 
has  been  thus  prepared,  a  "  tin  solution  "  is  prepared  as 
follows : — To  2  gallons  of  the  stronger  salt  solution  are 
added  2  quarts  of  oil  of  vitriol,  2  gallons  of  muriate  of 
tin  of  140°  to  150°  Twaddell,  28  gallons  of  muriatic  acid 
of  20°  to  30°  Baume,  and  2  gallons  of  nitric  acid  of  36° 
to  40°  B.  The  hides  are  tanned  by  being  immersed  in 
the  four  vats  successively,  1  pint  of  the  tin  solution  being 
first  added  to  the  solutions  in  vats  3  and  4,  and  1  pint 
added  to  each  of  these  solutions  whenever  a  fresh  lot  of 
hides  are  put  in.  The  colouring  liquor  first  described 
may,  if  desired,  be  made  without  sweet  fern,  or  ex- 


192  LEATHER  MANUFACTURE. 

clusively  from  sweet  fern.  The  tanning  is  said  to  occupy 
a  very  short  time,  and  the  leather  produced  is  stated  to 
be  "  exceedingly  tough  and  close  in  fibre." 

Casimir  Bez  and  Sons'  Process.* — This  invention  re- 
lates to  the  tanning  of  hides  by  aid  of  a  continuous  flow 
or  current  of  tan  liquor.  The  method  is  as  follows  :  the 
raw  hides  are  suspended  vertically  on  poles  arranged 
horizontally,  and  resting  across  the  tan-vats  or  pits, 
which  are  on  a  gentle  incline  to  encourage  the  flow  of 
the  liquid,  and  this  latter  is  made  and  contained  in  vats 
at  a  lower  level  than  the  tan-pits.  The  tanning  sub- 
stances are  deposited  on  a  grating  above  the  bottom  of 
the  pit  in  which  the  liquor  is  made,  so  that  this  pit  has  a 
double  bottom ;  in  the  lowest  portion  is  a  suction  and 
force-pump  for  raising  the  tanning  liquor  (made  in  this 
pit  by  admitting  water  above  the  tanning  materials)  to  a 
reservoir  above  this  pit,  and  a  little  above  the  tanning 
pits,  which  are  a  succession  of  vats  arranged  in  pairs. 
This  reservoir  is  provided  with  a  grating  near  the  top  to 
prevent  the  passage  of  solid  matters  held  in  suspension, 
and  being  filled  as  described  the  liquid  overflows  through 
an  aperture  at  the  top  of  the  first  pair  of  pits,  and  fills 
the  next  pair ;  passing  through  an  aperture  at  the  bottom 
of  the  pits,  it  again  fills  the  next  pair,  and  passes  through 
an  aperture  at  the  top,  and  so  on,  passing  through  open- 
ings alternately  top  and  bottom,  till  it  reaches  the  last 
Eit.  In  this  latter  a  pipe  enters,  and  by  a  gentle  slope 
jads  the  liquid  back  again  to  the  vat  or  leach,  in  which 
it  is  made  to  go  through  the  same  course  again,  so 
establishing  a  constant  flow  of  liquid  of  uniform  strength, 
the  skins  being  arranged  vertically  in  each  tanning-pit 
on  the  poles  running  longitudinally,  so  that  the  tanning 
liquor  thoroughly  washes  the  skins  on  all  sides  in  its 
passage,  and  so  impregnates  them  with  the  tannin. 
The  reservoir  containing  the  prepared  liquid  is  provided 
with  an  internal  agitator  to  prevent  any  deposit  that 
might  arise  from  being  in  a  state  of  rest.  When  a 
double  set  of  tan-pits,  and  two  pits  for  preparing  the 
liquors  are  employed,  the  same  arrangement  is  adhered  to, 


TANNING  PROCESSES.  J93 

and  then  a  double-branched  pipe  leads  the  liquor  from 
each  of  the  last  rows  of  vats  back  to  their  respective 
leachec. 

The  inventors  observe :  "  Many  systems  and  processes 
for  tanning  have  been  employed  for  replacing  pit-tanning 
— which  up  to  the  present  time  has  been  the  most  success- 
ful, both  in  an  industrial  and  economical  point  of  view. 
For  some  years  past  it  has  been  the  custom  to  place  hides 
in  the  pits  not  only  horizontally,  alternated  by  vegetable 
astringent  matters,  but  also  vertically,  suspended  across 
poles,  so  that  the  skins  hang  in  a  tanning  liquid ;  but 
this  arrangement,  whilst  submitting  all  parts  of  the  skin 
to  the  immediate  action  of  the  tannin,  has  nevertheless 
failed  to  produce  the  results  expected.  The  inventors 
attribute  this  to  the  decomposition  of  the  tan  liquor  by 
remaining  stagnant,  the  essential  parts  of  the  liquor 
precipitating,  so  that  in  a  short  time  the  skins  are  found 
in  a  mere  neutral  mass.  The  inventors  conceived  the 
idea  of  submitting  the  skins,  whilst  suspended  in  the  pits, 
in  a  position  parallel  to  each  other,  to  the  action  of  a 
tanning  liquid  which  continually  forms  a  double  current 
across  the  skins  and  passes  naturally  from  one  pit  to 
another,  reaching  the  upper  part  of  one  to  penetrate  to 
the  bottom  of  the  next  pit,  and  so  on  in  succession,  so 
that  the  constituents  of  this  tanning  liquid  are  constantly 
agitated  so  as  to  form  a  homogeneous  whole,  diminishing 
only  in  its  action  as  it  becomes  more  distant  from  its 
source  of  production/7 

Description  of  Drawings. — Fig.  32  is  a  section  following 
the  longitudinal  axis  of  the  pits  as  arranged,  and  as 
embodying  this  invention.  Fig.  33  is  a  plan  of  the  same, 
showing  a  twin  or  double  arrangement.  Fig.  34  is  a  detail 
on  a  larger  scale.  "  The  tannic  liquor  is  made  in  the  pits 
a  a,  at  the  head  of  the  construction,  and  below  the  tanning- 
pits,  the  reason  of  which  will  be  hereafter  explained.  The 
pits  a  a  have  double  bottoms  perforated  with  holes  b,  on 
which  the  vegetable  astringent  substances  are  placed.  The 
water  passing  through  these  substances  becomes  impreg- 
nated with  the  tannin  and  passes  under  the  bottom  ft,  having 


194 


LEATHER  MANUFACTURE. 


acquired  all  the  requisite  qualities.     A  suction  and  force- 
pump   6',  whose  suction-tube   c1,  debouches  between   the 


bottoms  of  the  pits,  transfers  the  tannic  liquid  to  the  lower 
part  of  the  juice  or  liquid-pit  d,  the  top  level  of  which' 
comes   above   a   grating  d1,  intended  to   stop   the   solid 


TANNING  PROCESSES.  195 

matters  held  in  suspension  in  the  liquid.  This  liquor 
pit  is  furnished  with  an  agitator  gifted  with  two  move- 
ments, an  up  and  down  penetrating 
motion  and  a  simultaneous  rotary  =n 
one.  In  this  manner  the  liquor, 
which  would  become  hard  from  rest, 
is  attacked  not  through  the  whole 
mass,  which  would  require  consider- 
able force,  but  progressively,  as  fast 
as  the  agitator  descends.  Following 
the  line  with  the  pit  d,  are  a  succes- 

r>       .,  i          •  i  licr.  34. 

sion  01  pits  more  or  less  in  number 

and  dimensions  fff1,   all   alike,  and  two   and   two,  all 

having  a  fixed  incline,  to  produce  a  natural  flow  of  the 

liquid  at  a  gentle  speed,  regulated  as  experience  may  prove 

requisite. 

"The  pits//have  their  sides  pierced  at  the  top  with  holes, 
#,  through  which  the  liquid  from  the  pit  d  reaches  the  first 
pit,  and  the  liquor  from  the  pit  fl  enters  the  second,  and 
so  on  in  succession  till  the  last  is  reached.  The  pits  /*, 
whose  sides  are  pierced  below  with  holes  //,  consequently 
receive  the  liquor  of  the  pits/  (which  precedes  them]  at  the 
bottom,  and  the  same  pits/  receive  it  at  the  top,  the  result 
being  that  the  liquor  from  the  reservoirs  dy  has  a  double 
flow  of  transfer  from  pit  to  pit,  and  of  ascent  and  descent, 
in  leaving  the  level  of  one  to  reach  the  bottom  of  the  next 
successively  until  the  last  is  reached.  In  this  a  pipe  k  is 
placed,  reaching  to  the  level  of  the  liquid,  and  being  gently 
sloped,  the  weakened  liquid  is  returned  to  its  source,  viz., 
the  pit  a,  and  being  renewed  and  strengthened,  it  is  then 
forced  by  the  pump  to  form  a  continuous  current.  In  the 
pits//1//1,  the  skins  to  be  tanned  are  suspended  on  wooden 
poles  m,  resting  across  the  partitions  of  the  pit,  all  the 
poles  being  arranged  parallel  with  the  direction  of  the  flow 
of  the  liquid.  The  skins  consequently  receive  the  action  of 
the  tannic  liquor  all  over  them,  which,  however,  becomes 
weaker  as  the  pits  are  further  separated  from  the  source  of 
origin  of  the  liquor,  which  is  then  returned  as  described  to 
acquire  renewed  strength.  As  the  strongest  liquors  are  the 


196  LEATHER  MANUFACTURE. 

most  dense,  deposits  are  left  at  the  bottoms  of  the  pits,  which 
are  occasioned  by  the  liquid  resting  all  night ;  no  ill  effects, 
however,  result  from  this,  the  skins  being  hung  in  the  pits 
with  the  thickest  parts  downwards.  Where  double  sets  of 
pits  are  used,  the  liquor  is  returned  to  the  leach  a  by  a 
bifurcating  pipe  k." 

After  the  skins  have  remained  long  enough  they  are 
removed  from  the  first  pit  and  replaced  by  those  from  the 
second,  and  then  by  the  third,  and  so  on  till  the  last  skins 
are  reached ;  these  are  then  put  into  the  first  pit,  and  fresh 
skins  placed  where  the  last  were  removed  from.  By  this 
arrangement  the  skins  throughout  the  pits  that  had  received 
the  action  of  the  tan  liquor,  from  the  top  to  the  bottom, 
now  receive  it  from  bottom  to  top. 

Snyder's  Process. — By  this  process  the  skins  are  sub- 
jected to  acupuncture  after  unhairing,  and  previous  to 
tanning.  The  skins  or  hides  are  punctured  with  small 
holes  partly  through,  or  are  perforated  with  holes  en- 
tirely through,  either  on  the  flesh  or  grain  side,  so  as  to 
admit  the  tannin  more  freely  and  perfectly  through  the 
skins.  The  best  time  for  performing  this  operation  is 
when  the  hide  or  skin  is  in  its  most  relaxed  state.  The 
punctures  may  be  made  either  with  a  hand  instrument 
with  steel  points,  or  by  passing  the  hide  under  or  over  a 
cylinder  or  flat  surface  covered  with  steel  points  inserted 
at  proper  distances,  varying  from  100  to  300  to  the 
square  inch. 

De  Bock's  Process. — This  process  consists  in  immersing 
the  skins  or  hides,  after  they  are  unhaired,  in  a  solution  of 
"mimosa  catechu,"  subjecting  them  to  handling,  then 
immersing  them  in  dilute  sulphuric  acid,  and  finally  in 
water.  In  treating  heavy  skins,  after  having  immersed 
them  in  the  solution  of  mimosa  catechu  and  handled  them, 
they  are  taken  out  of  the  pit  and  drained ;  a  solution  of  alum 
is  added  to  the  mimosa  solution,  as  also  a  little  vitriol,  which 
are  well  stirred  in.  The  patentee  states  that  in  place  of 
alum  a  solution  of  sulphate  of  magnesia  (Epsom  salts)  and 
mimosa  catechu  may  be  employed,  but  that  alum  makes 
the  hides  harder. 


TANNING  PROCESSES.  197 

Funcke's  Process. — 1.  The  unhaired  skins  or  hides  are 
passed  through  a  solution  of  commercial  soda,  and  then 
hung  up  until  nearly  dry  before  subjecting  them  to  the 
tanning  process.  2.  The  skins  are  immersed  in  a  solution 
of  bark  or  other  tanning  material,  to  which  is  added  a 
dilute  vegetable  acid.  By  this  solution  the  pores  of  the 
skins  are  opened  or  extended  while  being  exposed  to  the 
action  of  the  tannic  acid.  3.  The  skins  and  hides  are 
again  subjected  to  the  action  of  a  solution  similar  to 
the  above,  with  the  addition  of  a  stronger  solution  of 
the  vegetable  acid,  and  its  action  is  "  softened  "  or  molli- 
fied by  the  addition  of  a  solution  of  sugar.  Finally, 
while  the  skins  or  hides  are  subjected  to  the  usual  hand- 
ling, they  are  treated  with  a  solution  of  tannic  acid  until 
the  leather  is  finished  ;  but  since  the  tanning  liquor 
used  in  this  process  is  of  such  strength  as  to  impart  too 
deep  a  colour  for  most  purposes,  the  colour  is  reduced, 
when  requisite,  by  adding,  in  the  last  stage  of  the  pro- 
cess, sulphuric  acid  and  salt  to  the  tanning  liquor  in 
which  the  skins  are  worked.  The  skins  or  hides  are 
partially  dried  after  each  operation  before  being  submitted 
to  the  next. 

Earner's  Process. — The  inventor  says,  "  I  suspend  the 
hides  or  skins  within  an  air-tight  vessel,  so  that  the 
tanning  liquor  therein  may  come  in  contact  with  every 
part  of  each  hide ;  I  exhaust  the  air  from  the  tank,  and 
further  keep  the  tanning  liquor  in  motion  during  the 
process,  so  as  to  prevent  it  separating,  and  so  that  it  may 
sweep  off  from  the  hides  and  skins  the  film  of  spent 
liquor  immediately  it  is  formed.  The  apparatus  I  prefer 
to  employ  is  a  rectangular  wooden  tank  capable  of  being 
closed  air-tight  with  a  lid ;  within  this  tank  is  a  frame 
somewhat  shorter  than  the  tank,  and  capable -of  moving 
to  and  fro  endwise,  this  motion  being  given  to  it  by  a 
rod  which  is  attached  to  the  frame.  The  rod  passes  out 
through  a  stuffing-box  in  the  end  of  the  tank,  and  is  there 
connected  with  an  eccentric,  or  other  similar  instrument. 
The  frame  runs  backwards  and  forwards  in  the  tank  on 
suitable  guide  rails,  and  the  hides  or  skins  are  hung  on 


198  LEATHER  MANUFACTURE. 

laths  at  tide  other  end  of  the  frame,  transversely,  the  length 
of  the  tank.  As  the  hides  move  to  and  fro,  the  tanning 
liquor  presses  first  on  one  side  of  them  and  then  on  the 
other.  The  tank  is  connected  with  an  air-pump,  and  is 
exhausted  during  the  process.  Tanning  liquor  partially 
used  may  be  passed  from  one  tank  to  another,  and  air 
may  be  forced  into  the  tank  which  is  being  emptied,  and 
when  the  tank  is  emptied  may  be  forced  up  to  a  pressure 
of  5  or  6  Ibs.  to  the  square  inch,  so  as  to  press  out  the 
liquor  remaining  in  the  hides." 

Cox's  Process. — In  this  process  a  frame  is  used  with 
tranverse  bars  or  cords,  from  which  the  hides  to  be  tanned 
are  suspended.  The  bars  can  be  moved  to  and  fro,  so  that 
the  hides  may  be  made  to  touch  or  not,  as  desired.  The 
frames  can  be  lowered  into  or  hoisted  out  of  the  pit  by 
any  overhead  traveller  or  other  convenient  mechanism. 
Inclined  partitions  are  applied  to  the  pit,  which  are 
preferred  to  consist  of  parallel  fillets  or  bars,  the  edges  of 
which  approach  but  do  not  touch  each  other.  One  of 
these  is  at  each  end  of  the  pit,  but  more  may  be  used  if 
desired.  "When  the  hides  are  first  lowered  into  the  pit 
they  do  not  touch  each  other,  so  that  the  liquor  may  run 
freely  between  them.  After  a  time,  half  the  bars  are 
moved  towards  one  end  of  the  pit  and  half  towards  the 
other  end,  so  that  the  hides  rest  on  or  against  each 
other  and  against  the  inclined  partitions,  so  as  to  exclude 
the  passage  of  the  liquor  between  them.  The  hides 
are  immersed  in  these  two  ways  during  the  process  of 
tanning. 

Nossiter's  Process. — This  invention  has  for  its  objects, 
First,  to  employ  frames  or  partitions  to  keep  the  hides 
or  skins  separate  in  the  pits,  and  not  pressed  on  by  the 
hides  and*  skins  above.  Second,  pressing  several  hides 
or  skins  piled  together  in  a  press,  in  order  to  remove 
the  spent  liquor  before  again  immersing  them  in  fresh 
liquor. 

Description  of  the  Drawings. — In  tanning  hides  and 
skins  in  pits,  it  is  usual  to  pile  them  one  on  the  other,  so 
that  the  lower  ones  are  much  pressed  on,  and  the  tanning 


TANNING  PROCESSES. 


liquor  cannot  pass  to  the  two  surfaces  of  each  skin  or  hide, 
as  it  is  desirable  it  should  do.  In  each  figure  of  the 
drawings  the  same  letters  are  used  to  refer  to  the  same  parts. 
In  Fig.  35,  a  a  is  a  pit  of  the  ordinary  construction,  and 
in  place  of  having  the  hides  or  skins  placed  on  each  other 
in  the  liquor,  they  are  separated  by  means  of  frames  b  b, 
which  are  of  wood,  and  each  frame  simply  consists  of  a 
quadrangular  frame  with  crossbars,  there  bein<*  blocks,  b', 
to  keep  the  frames  separate,  so  that  a  skin  or  nide  placed 


Fig.  35. 

between  any  two  frames,  b,  will  not  press  on  a  skin  01 
hide  below,  nor  will  it  be  pressed  on  by  the  skins  or  hides 
above  ;  thus  leaving  each  hide  free  to  be  acted  on  by  tho 
tanning  liquor  in  every  part  of  its  surfaces,  which  will  be 
found  of  great  benefit  in  tanning  hides  and  skins,  and  the 
process  of  tanning  may  be  greatly  quickened ;  and  although 
a  pit  will  contain  less  hides  or  skins  by  these  means  than 
when  tanning  in  a  pit  in  the  ordinary  manner,  yet  more 
hides  and  skins  may  be  tanned  in  a  pit  in  a  given  time 
than  heretofore.  In  using  this  part  of  the  process,  the 
workman  will  withdraw  the  hides  or  skins  from  the  pit 
from  time  to  time,  and  submit  them  to  fresh  liquors, 
according  to  his  judgment,  as  usual.  The  hides  or  skins 


200 


LEATHER  MANUFACTURE. 


with  the  frames  are  first  placed  in  a  pit,  and  the  liquor  is 
then  run  or  pumped  into  the  pit.  Fig.  36  is  a  ground 
plan  of  the  frame. 

The  inventor  states  that  the  frames  or  partitions  may  be 
made  of  copper  or  any  other  material,  instead  of  wood, 
and  the  hides  separated  by  means  of  wire  or  network  of 
twine,  or  twigs,  and  also  by  bars  of  any  other  material, 
and  by  any  other  means  to  which  the  principle  of  the 
invention  can  be  applied.  Although  he  considers  it  is 


Fig.  36. 

better  that  each  hide  or  skin  should  be  by  itself,  yet  there 
may  be  two  or  more  placed  between  each  pair  of  frames 
or  partitions,  but  he  believes  there  will  be  proportionately 
less  beneficial  effect  from  this  arrangement ;  and  although 
he  prefers  that  the  skins  or  hides,  with  the  frames,  should 
be  in  a  horizontal  position,  yet  the  system  of  keeping  the 
hides  separate  may  be  carried  out  by  using  frames  such  as 
c  c,  Fig.  37,  and  fastening  or  lacing  the  hides  or  skins 
thereto  by  lacing  threads  d  d,  as  shewn,  the  frames  c 
having  blocks  c',  to  keep  them  separate.  Fig.  38  is  a  plan 
of  the  same. 

He  next  describes  the  second  part  of  his  invention, 
which  has  for  its  object  the  pressing  the  spent  liquor  out 
of  hides  or  skins  before  again  submitting  them  to  tanning 
liquor,  and  consists  of  using  a  suitable  press,  between  the 


TANNING  PROCESSES. 


201 


surfaces  of  which  a  number  of  hides  or  skins  are  piled,  and 
then  pressure  is  exerted  to  bring  the  pressing  surfaces,  e, 


Fig.  37. 


f,  of  the  press  to  approach  each  other,  and  thus  to  express 
the  liquor  therefrom.  The  drawings  (Figs.  39  and  40) 
show  one  description  of  press — a  screw-press,  where  the 


Fig.  38. 

pressure  is  obtained  by  means  of  a  screw  g,  acting  on  the 
surface  e,  and  the  other  press  (Figs.  41  and  42)  is  worked 


202 


LEATHER  MANUFACTURE. 


by  means  of  a  roller  h,  and  cords  i  i,  as  will  readily  be 
traced  on  examining  the  drawings.     These  or  other  presses 


Fig.  39. 

may  be  employed,  the  invention  consisting  of  piling  a  num- 
ber of  skins  or  hides  between  two  suitable  pressing  sur- 


Fig.  40. 

faces,  and  applying  pressure  thereto,  so  that  the  spent 
liquor  therein  may  be  expressed,  and  the  skins  or  hides 
rendered  better  capable  of  imbibing  fresh  tanning  liquor 
when  they  are  again  immersed  in  the  pits. 

Desmond's  Process. — In  this  process  the  inventor  em- 
ploys saturated  infusions  of  oak-bark  or  other  tanning  mate- 
rial, and  when  the  bark  is  exhausted,  he  extracts  what  gallic 
acid  is  left  by  fresh  water,  to  which  liquor  he  adds  j^Vo  part 
by  measure  of  sulphuric  acid.  In  this  liquor  the  hides  are 


TANNING  PROCESSES. 


203 


immersed  until  the  hair  is  easily  removed.  When  the 
swelling  is  necessary,  the  hides  are  immersed  in  water 
acidulated  with  0*05  parts  by  measure  of  sulphuric  acid, 


Fig.  41. 

for  ten  or  twelve  hours.     The  hides  are  then  washed  and 
fleshed,  and  are  next  immersed  for  a  few  hours  in  weak 


Fig.  42. 

tan  liquor,  the  strength  of  which  is  to  be  renewed  when  it 
becomes  exhausted,  till  the  skin  is  perfectly  tanned. 

Bnrbidge's  Process. — The  inventor  treats  the  hides 
with  the  extract  of  oak-bark,  which  he  says  he  obtains 
without  loss  of  tannin.  He  regulates  the  use  of  this  extract 
by  the  barkometer.  He  commences  with  a  weak  extract 
at  3°,  the  strength  of  which  is  increased  successively  by 
changing  the  liquor  three  times  a  week,  carrying  it  to  20°, 
the  strongest  liquor  being  used  when  the  tanning  is  near 
completion.  By  this  process  the  weight  of  the  leather  is 


204  LEATHER  MANUFACTURE. 

increased.  While  by  the  ordinary  process  it  takes  a  year 
to  tan  a  hide  weighing  80  Ibs.  when  green,  and  which  only 
weighs  40  Ibs.  when  tanned,  by  this  process  it  is  said  a 
similar  hide  can  be  tanned  in  three  months,  and  it  will 
weigh  40  Ibs.,  which  demonstrates  that  the  excess  of  time 
employed  is  injurious  to  the  leather.  The  amount  of  oak- 
bark  used  in  this  process  does  not  exceed  that  of  the  older 
methods,  being  about  four  or  five  pounds  for  every  pound  of 
leather. 

Kleman's  Process. — Oak-bark,  such  as  is  used  in  tanning 
skins,  is  usually  taken  off  while  the  tree  is  in  sap.  It  is 
dried  in  order  to  preserve  it,  and  it  is  introduced  into  the 
tanning-pit  at  the  same  time  as  the  skins,  together  with 
the  requisite  quantity  of  water.  But  it  will  be  understood 
that  the  tanning  property  as  well  as  the  chemical  composi- 
tion of  the  bark  must  vary  according  as  the  drying  is  quick 
or  slow,  and  the  greater  or  lesser  period  of  time  during 
which  the  bark  is  allowed  to  be  exposed  to  dampness  before 
the  tanning  begins.  In  most  cases  the  bark  commences 
to  undergo  acetous  fermentation,  which  is  completed  in  the 
tanning-vats.  In  order  to  utilise  the  tanning  principle, 
whether  obtained  from  oak-bark  or  gall  nuts,  to  the  best 
advantage,  M.  Kleman  recommends  the  following  method 
of  procedure.  The  bark,  while  still  fresh,  is  to  be  reduced 
to  small  pieces  and  placed  in  a  cask,  and  sufficient  water 
added  to  cover  the  material.  The  cask  is  then  to  be  her- 
metically closed,  so  as  to  prevent  the  action  of  the  oxygen 
of  the  atmosphere.  The  mixture  is  to  be  left  undisturbed 
for  a  few  weeks,  so  that  the  principles  soluble  in  water 
may  become  thoroughly  dissolved ;  after  this  the  liquor  is 
to  be  separated  from  the  bark.  If  the  liquor  be  now  heated 
to  from  113°  to  115°,  it  will  enter  into  vinous  fermentation, 
and  will  then  contain  enough  alcohol  to  mark  1°  to  2°.  If 
a  skin  be  placed  in  this  solution,  it  will  become  very  quickly 
tanned,  but  will  be  hard  and  horny,  owing  to  the  concen- 
trated condition  of  the  liquor.  If,  however,  it  be  diluted 
with  water,  excellent  results  will  be  obtained,  and  skins 
tanned  in  it  will  be  more  supple  and  the  grain  closer  than 
when  tanned  by  the  ordinary  method.  Moreover,  by  this 


TANNING  PROCESSES.  205 

method  the  same  quantity  of  bark  will  produce  more  tanning 
matter.  It  is  not  advisable  to  boil  the  bark  in  water, 
because  boiling  coagulates  the  albuminous  matter,  which 
induces  fermentation.  The  inventor  has  assured  himself, 
by  experiments,  that  bark  which  has  undergone  vinous 
fermentation  gives  much  better  results  than  tb«-t  which  has 
been  subjected  to  acetous  fermentation. 


CHAPTER  XV. 
TANNING  BY  PRESSURE. 

Spilsbury's  Process. — Drake's  Process. — Knowlys  and  Duesbury's  Pro- 
cess.— Fryer,  Watt,  and  Holmes's  Process. — Mouren's  Process. 

THE  readiness  with  which,  tannic  acid  combines  with 
the  unhaired  skin  causes  its  exterior  surfaces  to  become 
almost  immediately  converted  into  leather  after  immersion 
in  the  tanning  liquor,  by  which  the  absorbent  power  of 
the  skin  is  considerably  weakened,  and  the  interior  fibres, 
in  a  degree,  protected  from  the  action  of  the  tan.  To 
overcome  this  drawback,  and  to  favour  the  chemical 
action  of  the  tannin  throughout  the  entire  substance  of 
the  hide,  Spilsbury  devised  a  mechanical  method,  for 
which  he  obtained  a  patent  in  1823,  by  which  the  tannin 
was  forced,  by  hydrostatic  pressure,  through  the  pores  of 
the  skin,  and  thus  its  perfect  conversion  into  leather  was 
ensured.  The  process  is  as  follows  : — 

Spilsbury 's  Process. — The  hides  are  unhaired  and 
fleshed  in  the  usual  way,  after  which  they  are  carefully 
examined,  and  if  any  holes  are  discovered  these  are 
carefully  sewn  up,  so  that  the  skins  may  be  water-tight. 
Three  wooden  frames,  of  equal  dimensions,  are  fitted  to 
each  other,  and  the  edges  of  the  frames  secured  together 
by  screw-bolts.  A  skin  is  now  laid  upon  one  frame  and 
stretched  over  its  edges  ;  then  the  second  frame  is  placed 
upon  it,  so  that  the  edges  of  the  two  frames  may  pinch 
the  skin  all  round  and  hold  it  securely ;  another  skin  is 
then  stretched  over  the  upper  surface  of  the  second  frame 
in  a  similar  manner,  and  a  third  frame  being  placed  over 
this,  confines  the  second  skin.  The  three  frames  are  then 


TANNING  BY  PRESSURE.  207 

pinched  together  and  secured  tightly  by  the  screw-bolts 
passing  through  ears  set  round  their  outer  edges  ;  by  this 
means  the  skins  are  fixed  so  as  to  be  operated  upon  by  the 
tanning  infusion.  The  space  thus  formed  is  of  the 
nature  of  a  bag,  and  is  for  the  reception  of  the  tanning 
liquor,  which  is  introduced  as  follows :  The  frames  being 
set  upright,  a  pipe  connected  with  a  cistern  above  con- 
veys the  tanning  infusion  to  the  hollow  space  or  bag 
formed  by  the  two  skins.  The  air  is  allowed  to  escape 
by  a  stopcock  below,  which  is  closed  when  the  tanning 
liquor  is  introduced.  The  stopcock  connected  with  the 
cistern-pipe  is  kept  open  when  the  bag  is  filled  to  allow 
the  hydrostatic  pressure  to  force  the  tanning  liquor 
through  the  pores  of  the  skin  by  slow  infiltration,  whereby 
the  tannin  is  brought  in  immediate  contact  with  its  fibres. 
The  effect  of  the  pressure  shows  itself  by  a  continual 
sweating  of  the  tanning  liquor  at  the  outer  surfaces 
of  the  skins.  When  the  tanning  is  found  to  be  complete, 
the  upper  stopcock  is  closed,  and  the  lower  cock  opened 
to  allow  the  liquor  to  run  off.  Finally,  the  frames  are 
shifted,  the  bolts  unscrewed,  and  the  pinched  edges  of 
the  skins  cut  off,  after  which  they  are  dried  and  finished 
in  the  usual  way. 

Drake's  Process.— The  above  process  was  followed,  in 
1831,  by  a  patent  by  William  Drake,  a  tanner,  of  Bed- 
minster.  By  this  process  the  hides  were  in  the  first 
instance  immersed  in  a  weak  tan  liquor,  and  frequently 
handled  in  the  usual  manner,  by  which  they  became  par- 
tially tanned  before  being  submitted  to  the  infiltration 
process.  Two  hides,  as  nearly  as  possible  of  the  same  size, 
were  then  placed  with  their  grain  side  in  contact,  and  the 
two  edges  were  carefully  and  firmly  sewn  together  by 
means  of  shoemakers'  waxed  thread,  by  which  a  bag  cap- 
able of  holding  tan  liquor  was  formed.  This  bag  was 
then  suspended  by  loops,  sewn  to  its  shoulder  ends,  upon 
pegs  in  such  a  way  that  it  could  hang  within  a  wooden- 
barred  rack,  and  its  sides  pressed  together  in  a  book  form. 
The  upper  end  of  this  bag  was  left  unstitched  to  the  extent 
of  about  an  inch,  so  as  to  admit  a  funnel,  through  which 


208  LEATHER  MANUFACTURE. 

cold  tan  liquor  was  poured  until  the  bag  was  full.  After 
a  certain  time,  dependent  upon  the  texture  of  the  hides, 
the  outer  surface  of  the  bag  assumed  a  moist  or  sweaty 
condition,  and  drops  would  begin  to  appear  at  the  bottom 
of  the  bag,  which  were  received  in  a  vessel  placed  beneath. 
The  liquor  thus  collected  was  from  time  to  time  returned  to 
the  bag,  and  a  constant  supply  of  pure  tan  liquor  also 
introduced  into  the  funnel,  so  that  the  bags  were  always 
full.  When  the  hides  became  hard  and  firm,  while  being 
uniformly  damp  from  the  exudation  of  the  tan  liquor, 
the  temperature  of  the  apartment,  which  had  been  kept 
well  ventilated,  was  next  heated  gradually  to  from  70°  to 
150°  Fahr.,  and  the  heat  was  kept  up  until  the  hides 
became  harder  and  firmer  in  every  part.  As  soon  as  the 
hides  assumed  black  patches  in  places,  and  the  tanning 
liquor  ceased  to  diminish  in  strength,  the  tanning  was 
found  to  be  complete.  The  liquor  was  then  run  off  by 
cutting  a  few  stitches  at  the  bottom,  and  the  edges  of  the 
hides  were  then  pared,  and  they  were  dried  and  finished 
in  the  ordinary  way.  To  prevent  the  wooden  bars  within 
the  rack  from  disfiguring  the  hides,  the  bags  were  occa- 
sionally shifted  a  little  sideways.  It  is  stated  that  by  this 
process  hides  could  be  as  perfectly  tanned  in  ten  days  as 
in  as  many  months  by  the  ordinary  methods. 

Knowlys  and  Duesbury's  Process. — By  this  process 
the  hides  are  suspended  in  an  air-tight  vessel  of  rather 
larger  capacity  than  their  dimensions,  and  for  this  purpose 
it  is  lined  with  hooks,  upon  which  the  hides  are  hung  at 
regular  intervals,  and  kept  expanded  by  means  of  weights 
attached  to  their  lower  ends.  In  the  upper  portion  of  the 
vessel  or  vat  is  an  opening  with  a  movable  cover,  for  the 
entrance  of  the  workmen.  In  the  side,  near  the  top,  is  a 
tube  with  a  stopcock  and  coupling  screws,  for  connection 
with  an  air-pump,  and  in  a  corresponding  position,  on  the 
opposite  side,  is  a  similar  tube  for  the  admission  of  air,  to 
create  external  pressure,  if  required.  The  tanning  liquid 
having  been  introduced  until  it  covers  the  hides,  the  vessel 
is  hermetically  closed,  and  then  exhausted  of  air  by  means 
of  the  air-pump.  As  soon  as  the  vacuum  is  established, 


TANNING  BY  PRESSURE.  209 

the  contents  of  the  vat  are  kept  in  repose  for  a  day  and 
night,  after  which  the  tanning  liquor  is  drawn  off,  and  the 
apparatus  allowed  to  remain  empty  for  two  or  three  hours 
to  permit  the  admission  of  air.  This  manipulation  is  re- 
peated several  times,  or  until  the  hides  are  sufficiently 
tanned.  The  ooze  must  be  renewed  after  each  exhaustion 
of  the  vessel,  and  the  first  liquid  should  be  weak,  but  as 
the  operation  proceeds  its  strength  must  be  gradually 
increased.  This  means  of  promoting  hydrostatic  pressure 
by  the  aid  of  a  vacuum  is  stated  to  greatly  accelerate  the 
impregnation  of  the  hides  with  tannin,  and  the  process  is 
said  to  be  eligible  both  as  regards  quality  of  leather  and 
economy  of  time  and  labour.  The  air  being  withdrawn 
from  the  pores  of  the  skin,  its  resisting  action,  which  pre- 
vents the  rapid  penetration  of  the  ooze  with  the  skin,  is 
overcome. 

Fryer,  Watt,  and  Holmes's  Process. — The  object  of 
this  invention  is  to  tan  skins  and  hides  by  hydraulic 
pressure,  which  is  effected  as  follows  : — The  patentees 
say,  "  We  employ  round  upright  tanks,  to  be  made  air- 
tight, and  sufficiently  strong  to  bear  a  pressure  of  from 
10  to  12  Ibs.  to  the  inch,  according  to  the  time  intended  to 
be  given  in  the  process  of  tanning.  These  tanks  are  to  be 
fitted  internally  with  laths  or  hoops,  or  both,  to  attach 
each  skin  to  separately  at  its  full  length  ;  the  internal  fit- 
tings of  the  tank  to  move  upon  centres,  so  that  the  skins, 
when  once  placed  in  the  tank,  will  not  have  to  be  taken 
out  until  thoroughly  tanned.  The  skins  or  hides  having 
been,  arranged  in  their  places,  the  hydraulic  pump  is  then 
set  to  work,  which  forces  the  bark  liquor  (such  as  is  used 
in  the  old  process)  into  the  tanks  up  to  the  required 
pressure.  The  bark  liquor  being  now  in  the  tanks,  the 
fittings,  with  the  skins,  should  be  moved  about  four  times 
a  day  for  the  first  three  or  four  days  ;  at  the  end  of  that 
time  to  be  moved  twice  a  day,  and  at  the  end  of  the  fifth 
day  once,  until  thoroughly  tanned.  The  liquor  is  then 
to  be  drawn  off,  the  skins  removed  and  others  substituted 
for  them,  to  be  treated  in  like  manner." 

Mouren's  Process. — By  this  method  a  vessel,  capable  of 

P 


210  LEATHER  MANUFACTURE. 

withstanding  the  pressure  it  is  to  be  subjected  to,  is  lined 
with  lead,  and  it  is  furnished  with  manholes  in  the  cover, 
which  are  made  to  screw  on  and  off.  Connected  with,  or 
standing  upon,  a  vat  containing  tanning  liquid,  are  placed 
two  pumps,  one  communicating  with  the  upper  part  of  the 
vessel,  and  the  other  opening  into  a  channel  running  up 
and  down  the  side  of  the  vessel,  and  which  is  perforated. 
The  skins  are  placed  in  the  vessel  between  two  layers  of 
tan  ;  tanning  liquid  is  pumped  into  the  vessel  at  the  upper 
part,  and  the  entire  vessel  is  filled ;  the  pump  communi- 
cating with  the  perforated  channel  is  then  used  to  force  in 
more  tanning  liquid  to  any  required  pressure,  which  is 
denoted  by  a  gauge  on  the  pipe  leading  into  the  channel. 
The  skins  or  hides  are  kept  under  pressure  for  periods 
varying  with  their  nature  and  the  purposes  to  which  they 
are  to  be  applied.  The  operation  may  be  performed  once 
or  of  tener. 


CHAPTER  XVI. 
QUICK  TANNING. 

Quick  Tanning. — Dr.  "Ore's  Views. — Dussauce's  Observations. — Dietz's 
Process.  -  Needham's  Process. — Nuessly's  Process.— Bell's  Process. — 
Baron's  Process.— Another  Quick  Process.— Guiot's  Process. — Danish 
Quick  Process. 

Quick  Tanning.— When  we  consider  that  by  the  old  pro- 
cesses of  tanning  the  conversion  of  hides  and  skins  into 
good  leather — and  it  was  good — frequently  occupied  a 
period  of  about  a  year  and  a  half,  it  is  not  to  be  wondered 
at  that  attempts  should  have  been  made  to  reduce  the  time 
required  for  perfect  tanning  by  other  means  than  those 
ordinarily  adopted.  In  these  days,  with  our  greatly  in- 
creased population  and  vast  export  trade,  if  we  were  de- 
pendent upon  the  old  slow  processes  of  manufacture,  and 
upon  oak- bark  alone,  how  many  of  the  industrial  popula- 
tion would  be  compelled  to  go  barefoot ! 

It  has  often  been  remarked  that  science  has  done  less  to 
improve  the  tanning  art  than  has  been  the  case  with  many 
other  chemical  industries.  This  is  doubtless  true  to  a 
certain  extent ;  but  it  cannot  be  denied  that  from  the 
moment  the  principles  of  the  art  were  discovered  and 
explained,  commenced  that  great  change  in  the  modus 
operandi  which  has  ever  since  been  working,  by  slow 
degrees  it  is  true,  to  develop  a  more  speedy  yet  equally 
good  method  of  tanning  than  that  pursued  up  to  the 
latter  part  of  the  eighteenth  century.  That  the  process 
of  tanning  can  never  be  both  quick  and  good,  has  been 
demonstrated  by  long  years  of  experience  almost  beyond 
the  shadow  of  a  doubt.  But  that  there  is  a  mean  between 


212  LEATHER  MANUFACTURE. 

the  very  quick  and  the  very  slow  methods,  which  has  now 
been  arrived  at,  must,  we  think,  be  admitted. 

That  the  conversion  •  of  gelatine  into  leather,  or  rather 
into  tanno-gelatine,  is  not  of  itself  a  slow  process  is  proved 
by  the  avidity  with  which  that  substance  combines  with 
tannin  the  moment  these  substances  come  in  contact  with 
each  other ;  but,  in  the  case  of  a  hide  immersed  in  tan- 
ning liquor,  when  once  this  effect  has  taken  place  upon 
its  superficial  surfaces,  its  powers  of  absorption — no  matter 
to  what  extent  the  pelt  may  have  been  raised  or  swollen — 
are  materially  diminished,  and  before  the  tannin  can  find 
its  way  to  the  interior  fibres  of  the  skin  it  must  of 
necessity  remain  for  a  lengthened  period  in  the  tanning- 
liquor.  Now  it  might  naturally  be  thought  that  if  by  any 
plan  the  tan  liquor  could  be  forced  throughout  the  entire 
structure  of  the  skin,  and  thus  all  its  fibres  brought  in 
direct  contact  with  the  astringent  principle,  that  the 
operation  of  tanning  would  be  rendered  an  almost  instan- 
taneous process.  But  is  this  so  in  fact  ?  We  know  that 
by  Spilbury's  and  Drake's  ingenious  processes  the  tannin 
was  forced  through  the  skins  by  hydrostatic  pressure,  until 
it  eventually  appeared  on  the  external  surfaces  in  the  form 
of  a  perspiration ;  but  though  this  would  unquestionably 
prove  that  the  astringent  matter  had  -permeated  the  entire 
structure  of  the  skin,  would  not  the  conditions  under  which 
the  tannin  was  introduced  keep  the  skin  porous  when  the 
operation  was  complete  ?  Would  even  the  after  process  of 
drying — which  would  naturally  close  the  pores  to  some 
extent — enable  the  leather  to  acquire  that  hardness,  firm- 
ness, and  absence  of  porosity  which  slowly  tanned  leather  is 
known  to  possess  ?  In  other  words,  although  skins  tanned 
by  hydrostatic  pressure  would  shrink  and  become  more  or 
less  compact  and  firm  after  drying,  would  not  moisture 
again  dilate  the  pores  when,  say,  boot- soles  made  from  such 
leather,  were  subjected  to  the  effect  of  wet  ?  In  the 
ordinary  slow  process  of  tanning  the  expansion  of  the 
pores,  beyond  that  which  is  induced  by  the  process  of 
raising,  would  not  take  place,  but  rather,  by  the  weight 
of  hides  and  tan  in  a  well-filled  pit,  the  pores  of  the  skin 


QUICK  TANNING.  213 

would  be  more  likely  to  become  closed  to  some  extent 
while  the  skin  was  wet,  and  would  become  still  more  con- 
tracted during  the  after  process  of  drying. 

We  would  ask,  does  not  the  process  of  tanning  mean 
something  more  than  the  mere  conversion  of  the  gelatine 
of  the  hide  into  the  chemical  substance  called  tcuuw-gcla- 
tine  ?  As  Sir  Humphry  Davy  believed  to  be  the  case,  does 
not  the  slow  absorption  of  vegetable  extractive  constitute 
an  important  and  necessary  feature  in  the  formation  of 
leather  ?  And  if  so,  may  not  the  union  of  gelatine,  tannin, 
and  vegetable  extractive  be  naturally  a  slow  process  ?  If 
this  be  the  case,  we  have  merely  to  determine  how  lony  the 
process  actually  takes  under  the  most  favourable  conditions. 
The  actual  period  may  be  far  short  of  the  time  allotted  to 
the  process  by  the  old  tanners — as  it  would  naturally  be 
when  ooze  is  employed  instead  of  water  with  the  tan 
stratified  with  the  hides;  on  the  other  hand,  allowing 
for  the  advantage  in  speed  which  liquid  tan  must  pre- 
sent, the  period  necessary  to  convert  hides  into  perfect 
leather  may  naturally,  under  the  most  favoured  conditions, 
be  slow. 

Dr.  Tire's  Views. — Upon  this  subject  Dr.  Ure  makes 
the  following  important  observations,  and  his  reasoning, 
based  upon  Sir  Humphry  Davy's  expressed  views  on  the 
one  hand,  and  the  experience  of  practical  workmen  on  the 
other,  clearly  indicates  that  not  only  is  vegetable  extrac- 
tive a  necessary  constituent  of  leather,  but  that  its  union 
with  the  gelatine  of  the  skin  and  tannin  is  essentially  a 
slow  process.  "When  calf-skin  is* slowly  tanned  in  weak 
solutions  of  the  bark,  or  of  catechu,  it  combines  with  a  good 
deal  of  extractive  matter  ;  and  though  the  increase  of  the 
weight  of  the  skin  be  comparatively  small,  yet  it  has  be- 
come perfectly  insoluble  in  water,  forming  a  soft  but  at  the 
same  time  strong  leather.  The  saturated  infusions  of 
astringent  barks  contain  much  less  extractive  matter  in 
proportion  to  their  tannin  than  the  weak  infusions ;  and 
when  skins  are  quickly  tanned  in  the  former  they  produce 
a  worse  and  less  durable  leather  than  when  tanned  in  the 
latter.  In  quick  tanning  a  considerable  quantity  of 


214  LEATHER  MANUFACTURE. 

vegetable  extractive  matter  is  thus  lost  to  the  manu- 
facturer, which  might  have  been  made  to  enter  as  a  useful 
constituent  into  the  leather.  These  observations  show 
that  there  is  sufficient  foundation  for  the  opinion  of  the 
common  workmen  concerning  what  is  technically  called 
feeding  of  leather  in  the  slow  method  of  tanning;  and 
though  the  processes  of  this  art  have  been  unnecessarily 
protracted  by  defective  methods  of  steeping  and  want  of 
progressive  infiltration  of  the  astringent  liquor  through 
the  skins,  yet  in  general  they  appear  to  have  arrived,  in 
consequence  of  old  experience,  at  a  degree  of  perfection 
in  the  quality  of  the  leather  which  cannot  be  far  ex- 
ceeded by  means  of  any  theoretical  suggestions  which 
have  been  advanced." 

According  to  the  foregoing  remarks,  there  would 
appear  to  be,  as  we  have  suggested,  an  exact  point,  per- 
haps now  determined,  when  the  tanning  process  is  known 
to  be  complete,  without  unnecessarily  protracting  the 
operation  on  the  one  hand,  or  unduly  hastening  it  on 
the  other.  The  tanning  strength  of  the  liquors  being 
always  uniform  (though  progressively  varying  in  propor- 
tions of  tannin),  and  the  changes  of  temperature  allowed 
for  and  calculated,  might  not  the  actual  period  requisite 
to  produce  a  perfect  leather  be  determined  by  a  consecu- 
tive series  of  trials  ? 

Dr.  Ure  further  remarks,  "On  the  first  view  it  may 
appear  surprising  that  in  those  cases  of  quick  tanning 
where  extractive  matter  forms  a  certain  portion  of  the 
leather,  the  increase  of  weight  is  less  than  when  the  skin 
is  combined  with  the  pure  tannin ;  but  the  fact  is  easily 
accounted  for,  when  we  consider  that  the  attraction  of 
skin  for  tannin  must  be  probably  weakened  by  its  union 
with  extractive  matter ;  *  and  whether  we  suppose  that 
the  tannin  and  extractive  matter  enter  together  into 
combination  with  the  matter  of  the  skin,  or  unite  with 
separate  portions  of  it,  still,  in  either  case,  the  primary 

*  Considering  the  superior  affinity  of  tannic  acid  for  gelatine  over 
vegetable  extractive,  is  it  not  the  former  which  retards  the  absorption  of 
the  latter  ? 


QUICK  TANNING.  215 

attraction  of  the  skin  for  tan  must  be  to  a  certain  extent 
diminished.  In  examining  astringent  vegetables  in  rela- 
tion to  their  power  of  making  leather,  it  is  necessary  to 
take  into  account  not  only  the  quantity  they  may  contain 
of  the  substance  precipitable  by  gelatine,  but  likewise  the 
quantity  and  the  nature  of  the  extractive  matter  ;  and  in 
cases  of  comparison,  it  is  essential  to  employ  infusions  of 
the  same  degree  of  concentration." 

In  applying  any  of  the  quick  tanning  processes,  the 
principles  indicated  in  the  above  observations  must  not  be 
lost  sight  of,  while  the  practice  must  be  in  accordance 
with  ascertained  facts ;  otherwise  the  production  of  good 
leather  may  be  more  accidental  than  certain,  even  if  it 
does  not  become  impracticable. 

Dussance's  Observations. — As  to  the  time  necessary  for 
the  conversion  of  hides  into  leather,  Dussauce  says,  "  Many 
tanners  maintain  that  there  is  no  advantage  whatever  in 
keeping  leather  in  process  after  the  tannin  and  gelatine  have 
united.  There  is  much  diversity  of  opinion  upon  the  length 
of  time  necessary  or  advantageous  to  keep  leather  in  the 
tanning  liquor,  but  it  doubtless  depends  very  much  upon 
the  preparation  of  the  hide.  Tanners  generally  do  not 
pay  proper  attention  to  the  early  steps,  those  of  unhairing 
and  raising.  Is  there  any  necessity  that  time  be  given 
after  the  tannin  and  gelatine  have  united  for  leather  to 
consolidate  and  grow  ?  Is  there  any  gain  in  weight,  if 
even  made  more  durable  by  the  delay  P  "  According  to 
lire's  views,  and  the  observations  of  the  practical  work- 
men to  whom  he  has  referred,  an  affirmative  answer  must 
be  given  to  these  two  questions,  if  by  "feeding  the 
leather/'  we  are  to  understand  giving  the  hides  sufficient 
time  to  take  up  as  much  vegetable  extractive  as  they  are 
capable  of  doing,  and  which,  in  a  sense,  would  be  allow- 
ing the  leather  to  grow  or  its  weight  to  become  increased 
by  the  slow  process  necessary  for  the  absorption  of 
vegetable  extractive. 

Again,  Dussance  asks,  "  What  length  of  time  is  it 
necessary  to  let  hides  tan  which  are  limed  or  sweated  in 
the  common  method  ?  These  are  questions  often  asked, 


si6  .  LEATHER  MANUFACTURE. 

and  on  which  the  views  of  practical  men  are  desired.  The 
fact  is,  that  when  the  tannin  and  gelatine  are  completely 
united,  the  process  of  the  formation  of  leather  is  ex- 
hausted." 

If  vegetable  extractive  were  not,  as  it  has  been  proved 
by  Davy  to  be,  a  necessary  constituent  of  solid  leather, 
this  statement  of  Dussauce  might  be  fully  accepted  ;  but 
we  unhesitatingly  give  the  preference  to  the  views  of  Davy 
and  lire,  because  we  believe  that  leather,  properly  so 
called,  is  a  compound  of  gelatine,  tannin,  and  vegetable 
extractive,  and  not  merely  tanno- gelatine.  "  But  in  the 
ordinary  manufacture,"  Dussauce  continues,  "  it  is  never 
the  case  that  the  hide  has  received  all  the  tannin  [and 
extractive  ?]  of  which  it  is  capable,  and  therefore  the 
extension  of  time  is  followed  by  an  increase  of  weight. 
If  all  the  gelatine  of  the  hide  could  be  exposed  at  the 
same  moment  to  the  action  of  the  tannin,  the  process 
would  be  instantaneous."  True ;  but  the  product  would 
be  tanno- gelatine  and  not  leather  proper.  "  There  is  no 
doubt  that  the  improvements  in  this  direction  [quickening 
the  tanning  process]  are  feasible,  and  that  a  considerable 
time  is  now  actually  gained  over  the  old  periods  of 
manufacture  without  any  injury  to  the  leather.  But  no 
improvement  has  yet  so  facilitated  the  quick  production  of 
leather  that  a  material  gain  in  weight  may  not  be  secured 
by  a  protracted  stay  in  the  vats ;  while  attempts  of  this 
kind,  by  the  use  of  deleterious  substances,  have  resulted 
in  rotting  the  fibre  of  the  hide.  Has  there  ever  been  any 
leather  tanned  in  two,  three,  or  six  months,  by  any 
patented  process,  which  has  claimed  to  be  equal  to 
English  bark  leather  ?  And  what  gives  the  great  superior- 
ity of  this  class  of  leather,  if  not  the  length  of  time  it  is  in 
the  tan  ?  "  Undoubtedly  a  protracted  exposure  to  the 
tan  would  give  the  superiority  referred  to,  but  is  it  not 
due  to  the  vegetable  extractive,  and  not  the  tannin, 
entering  into  the  substance  of  the  hide  after  the  gelatine 
of  the  skin  has  become  converted  into  tanno-gelatine  ? 
Does  not  the  term  "feeding"  the  leather  really  mean 
allowing  time  for  the  hide  to  take  up  as  much  vegetable 


QUICK  TANNING.  217 

extractive  as  it  is  capable  of  doing,  whereby  not  only  is 
its  weight  increased  but  its  quality  improved  ?  * 

"  It  is  well  known,"  says  Dussauce,  "  that  the  oak 
tanners  of  Pennsylvania  and  Maryland  are  about  twice  as 
long  in  tanning  leather  as  the  hemlock  tanners.  May  it 
not  be  this  length  of  tanning  which  gives  the  general 
superiority  to  oak  leather?  It  is  a  general  complaint 
that  leather  tanned  by  quick  processes  is  wanting  in  solidity 
and  strength.  It  is  porous,  easily  filled  with  water,  and 
wanting  in  durable  qualities."  These  observations,  like 
those  from  the  same  authority  previously  quoted,  tend 
materially  to  strengthen  the  views  propounded  by  the 
gifted  observer  Davy,  to  whose  clear  and  original  mind 
we  are  indebted  for  so  much  that  is  valuable  both  to 
science  and  to  art. 

We  have  been  tempted  to  dwell  thus  far  upon  the 
comparative  advantages  and  disadvantages  of  the  slow  and 
quick  methods  of  tanning,  in  order  that  the  reader,  bearing 
in  mind  the  support  which  practice  has  given  to  theory, 
may  more  readily  form  his  own  judgment  upon  the 
merits  of  the  various  processes  which  will  hereafter  be 
submitted  to  his  consideration. 

Dietz's  Process. — The  object  of  this  invention  is  to 
swell  the  tissues  and  fibres  of  the  skin  previous  to,  and 
during  the  process  of  tanning,  by  the  employment  of 
saline  liquors,  whereby  the  skin  is  stated  to  be  more 
readily  affected  by  the  tanning  material ;  and  in  using  in 
connection  with  such  saline  liquors  tanning  liquors  of 
different  and  increasing  strength,  by  which  the  centre 
and  inner  parts  of  the  skin  are  tanned  as  quickly,  or 
nearly  so,  as  the  outer  surfaces.  The  inventor  makes  a 
weak  liquor,  at  2°  or  3°  of  the  barkometer,  from  any 
tanning  material.  In  this  liquor  he  mixes  salt  or  alum  in 
the  proportion  of  two  ounces  to  the  gallon,  and  combines 
the  whole  by  well  stirring.  The  skins  are  immersed  in 
this  liquor  and  handled  till  they  are  saturated  and  the 
fibre  fully  swollen.  The  saline  substances  may  be  dissolved 
in  water  alone,  without  any  tanning  material,  and  the 

*  And  which  would  not  be  attained  if  tan  liquor  only  were  used. 


2i8  LEATHER  MANUFACTURE. 

skins  saturated  with  this  liquor,  and  after  complete  satura- 
tion they  are  passed  into  the  tanning  bath.  The  strength 
of  the  bath  is  to  be  increased  from  2°  to  4°  every  day,  and 
the  skins  stirred  and  handled  until  they  are  tanned.  The 
time  required  for  tanning  by  this  process  is — 

For  sheep  skins 2  or  3  days. 

„  calf  skins 8  days. 

„  heavy  leather    30  to  40  days. 

„  sole     40  to  50    „ 

Needham's  Process. — In  carrying  out  this   process  a 
bath  is  prepared  consisting  of — 


1  peck. 

Hops I   1  lb. 

Sal  soda  (soda  crystals) J  „ 

Animal  brain £  ,, 

The  whole  of  the  above  are  boiled  in  8  gallons  of  water, 
and  when  ready  is  to  be  diluted  with  40  gallons  of  water. 
The  hides  are  soaked  in  this  solution  from  six  to  thirty- six 
hours.  They  are  put  into  a  tanning  solution  composed  of — 

Catechu 12  Ibs. 

Divi  divi    4  ,, 

Alum 4  ,, 

Salt    2  „ 

The  novelty  in  this  process  consists  in  treating  the 
hides  in  the  above  solution  preparatory  to  immersing  them 
in  the  tanning  liquor. 

Nuessly's  Process.— The  inventor  first  makes  a  solu- 
tion composed  of — 

Pyroligneous  acid  (wood  vinegar) 1  gallon. 

"Water 3  gallons. 

Hydrochloric  acid    , 4  ounces 

Catechu If  lb. 

Alum fib. 

The  whole  of  these  are  to  be  well  mixed  together  by 
stirring.  To  100  gallons  of  the  above  solution  he  adds — 

Catechu 40  Ibs. 

Alum 10  Ibs. 


QUICK  TANNING.  219 

The  hides  are  to  be  immersed  in  this  bath,  when  in 
three  or  four  days  they  will  be  tanned.  Heavy  hides 
require  three  or  four  weeks. 

Bell's  Process.— The  hides  being  unhaired  and  prepared 
as  usual,  are  to  be  immersed  in  tanning  liquor  from  two 
to  four  days.  The  tanning  liquor  is  composed  of — 

Wood-ashes 1  bushel. 

Water    60  gallons. 

After  settling,  draw  off  40  gallons ;  to  this  is  added 
40  Ibs.  of  terra  japonica,  and  the  whole  boiled  until  the 
latter  is  dissolved.  When  cold,  the  solution  is  ready 
for  use.  The  inventor  says  that  by  the  combination 
of  the  alkaline  ley  and  tannin  he  is  enabled  to  prevent 
the  tanning  liquors  from  becoming  sour  or  decomposed,  and 
he  is  enabled  to  strengthen  them  without  accumulating 
more  than  is  necessary,  and  the  skins  will  tan  in  a  shorter 
time  and  with  less  labour  than  by  other  processes. 

Baron's  Process. — By  this  process  the  hides  are  pre- 
pared in  the  usual  manner,  excepting  that  they  are  soaked 
for  three  or  four  hours  in  river  water,  containing  jVinr  °^ 
hydrochloric  acid,  to  neutralise  any  lime  present  in  the 
skins ;  they  are  afterwards  washed  in  river  water.  This 
treatment  with  the  dilute  acid  completes  the  perfect  swel- 
ling of  the  hides,  and  they  are  ready  for  tanning.  Before 
tanning,  however,  the  colour  of  the  leather  must  be  fixed, 
so  as  to  be  of  the  usual  shade.  For  this  purpose  an 
infusion  of  oak-bark  at  1°  by  the  barkometer  is  taken,  and 
to  which  -j-J-0-  of  madder  is  added.  The  hides  are  immersed 
in  this  bath  for  six  hours,  so  that  the  colour  may  be  uni- 
form. They  are  left  to  rest  for  an  hour,  then  turned  over 
every  hour.  After  twenty-four  hours  the  hides  are  ready 
for  tanning  in  the  following  manner  :  Dissolve  catechu  in 
river  water,  according  to  the  number  of  hides  to  be 
tanned.  The  liquor  is  placed  in  a  receiver  covered  with 
a  filter  and  provided  with  a  "rubber"  pipe  to  transfer 
the  liquor  to  the  vats.  The  first  vat  contains  liquor  at  1°, 
with  a  weak  solution  of  alum.  Into  this  the  hides  are 
placed,  and  are  occasionally  stirred  during  the  first  two 


220  LEATHER  MANUFACTURE. 

hours ;  afterwards  they  are  handled  every  three  hours.  Next 
day  they  are  placed  in  a  vat  containing  liquor  at  2°,  and 
handled  four  times  a  day,  then  allowed  to  drain  two  hours. 
The  strength  of  liquor  is  to  be  increased  from  day  to  day, 
until  the  hides  are  well  tanned,  when  they  are  finished  in 
the  usual  manner. 

Another  Quick  Process — To  carry  out  this  process 
air-tight  copper  vessels  are  used.  When  the  hides  are 
taken  from  the  washing  water  the  moisture  is  expelled  by 
pressure ;  the  hides  are  then  packed  in  a  drum  fixed  so 
as  to  have  a  rotary  motion,  and  with  them  the  necessary 
amount  of  tanning  material  is  mixed,  together  with  suffi- 
cient water  to  keep  the  contents  of  the  vessel  moist.  The 
main  hole  of  the  drum  is  now  closed,  and  the  air  pumped 
out  as  completely  as  possible.  This  being  done,  the  stop- 
cock is  closed  and  a  piece  of  lead  pipe  is  added  to  the 
conducting  tube.  This  lead  pipe  communicates  with  a  tank 
containing  tanning  liquor  of  proper  strength.  If  the 
stopcock  be  now  opened,  the  tanning  liquor  rushes  rapidly 
into  the  drum,  and  when  a  sufficient  quantity  has  been 
admitted  the  stopcock  is  closed  and  the  drum  rotated  for 
an  hour,  or  half  an  hour,  according  to  the  quantity  of  hides 
contained  in  it.  After  two  or  three  hours'  rest  the 
rotation  is  again  resumed,  and  continued  until  the  operation 
is  complete.  The  advantages  of  this  process  are  said  to  be 
that  the  pores  of  the  skins  are  opened,  and  the  tannin  is 
not  so  quickly  converted  into  gallic  acid.  The  rotary 
motion  facilitates  the  solution  of  the  tannic  acid  of  the 
bark,  and  helps  its  absorption  by  the  hides,  which  are 
tanned  in  less  time  than  without  rotary  motion.  The 
following  table  shows  the  time  occupied  in  tanning  with 
and  without  rotary  motion : — 

Without  rotary  motion.     With  rotary  motion , 
Calf  skins  from 6  to  11  days     .  4  to    7  days 


Horse  hides    35  to  40  days 

Lighter  hides 30  to  35  days 

Middling  cow  hides,' 40  to  45  days 

Heavy  cow  hides  . .' 50  to  60  days 

Ox  hides,  light 50  to  60  days 

Ox  hides,  first  quality 70  to  90  days 


14  to  18  days 
12  to  16  days 
18  to  20  days 
22  to  30  days 
20  to  30  days 
35  to  40  davs 


QUICK  TANNING.  221 

By  the  above  process  a  large  percentage  of  bark  is  said 
to  be  saved. 

Gniot's  Process. — The  hides  are  depilated  and  raised  as 
usual.  Fifty  hides  are  then  treated  in  a  vat  of  the  fol- 
lowing dimensions:  width  3  feet,  and  height  4J  feet. 
The  proportions  of  materials  used  for  fifty  hides  are — 

Catechu ' 150  Ibs. 

Water     50  gals. 

Stir  well  until  dissolved,  and  add  50  gallons  of  fresh 
water,  and  a  solution  containing  3  Ibs.  of  lime  ;  mix  well 
together.  The  hides  are  to  be  immersed  in  this  bath  for 
eight  weeks.  During  the  first  two  weeks  they  are  to  be 
handled  once  a  day ;  the  last  six  weeks  they  are  to  bo 
handled  only  once  a  week.  Another  bath  is  to  be  prepared 
by  taking  25  gallons  of  the  above  liquid  which  has  been 
used,  and  adding  to  it  25  gallons  of  fresh  water  and  6  Ibs. 
of  white  vitriol  (sulphate  of  zinc).  These  are  to  be  mixed, 
and  the  hides  placed  in  this  bath  for  four  days,  with  stir- 
ring every  day.  The  hides  are  then  removed  and  put  into 
125  gallons  of  fresh  water,  in  which  they  are  left  for  three 
days,  when  the  operation  is  complete,  and  they  are  finished 
as  usual. 

Danish  Quick  Process. — The  following  rapid  method 
of  tanning,  by  which  "  dressing  leather  "  may  be  tanned 
in  two  months,  is  practised  in  Brittany  anil  elsewhere. 
The  skins  are  first  unhaired  and  fleshed  as  usual ;  they 
are  then  coloured  by  being  barley  and  tan  dressed,  like 
barleyed  skins,  after  which  they  are  sewn  up  in  the  form 
of  bags,  apertures  of  about  ten  inches  in  length  being 
left,  through  which  they  are  filled  with  tanning  solution. 
These  openings  being  then  sewn  up,  the  closed  bags  are 
forcibly  beaten  all  over  for  the  purpose  of  distributing 
their  contents  equally  throughout.  They  are  then  deposited 
in  pits  containing  sufficient  ooze  to  cover  them  completely, 
these  pits  being  4J  feet  deep,  the  same  width,  and  8J  to 
lOJ  feet  long.  When  submerged  in  the  pits,  planks 
heavily  weighted  with  large  stones  or  weights  are  placed 
upon  the  skins,  so  as  to  press  them  down  forcibly  towards 


222  LEATHER  MANUFACTURE. 

the  bottom,  to  increase  the  penetrating  power  of  the  in- 
fusion ;  and  in  order  that  they  may  be  equally  tanned  on 
their  different  sides  the  planks  are  removed  three  or  four 
times  a  week,  and  the  bags  are  again  thoroughly  beaten 
and  their  position  changed. 

Skins  prepared  in  this  way  are  supple  and  pliable  like 
crop  leather,  and  have  a  finer  colour  than  strong  leather, 
but  they  are  thinner  than  those  made  in  the  ordinary  way, 
owing  to  their  not  swelling  up  by  the  slow  process  of 
feeding,  and  also  from  the  pressure  from  within  and 
without  to  which  they  have  been  subjected.  "  It  is 
possible,"  says  Morfit,  "  that  the  improvement  of  this 
process,  which  is  now  the  old  method  combined  with  that 
devised  by  Seguin,  may  offer  many  advantages.  The 
external  and  internal  pressure  mutually  assisting,  must 
certainly  promote  the  introduction  of  tannin  and  extractive 
into  the  tissue  of  the  skin.  It  is,  however,  doubtful  if 
the  durability  and  other  qualities  of  the  product  are  equal 
to  those  of  leather  prepared  by  more  tedious  processes  " — 
an  observation  which  is  more  or  less  applicable  to  every 
other  process  of  quick  tanning. 


CHAPTER  XVII. 
HARNESS  LEATHER    TANNING. 

Harness  and  Upper  Leather.— Crop  Leather. 

Harness  and  Upper  Leather.  —  The  preparation  of 
leather  to  be  dressed  for  harness  and  boot  uppers  is  in 
many  respects  different  from  that  adopted  for  butt  or  sole 
leather ;  and,  as  will  be  readily  understood,  it  must  possess 
the  utmost  degree  of  toughness  and  strength  which  it  is 
possible  to  obtain  by  the  most  careful  means,  from  the  first 
selection  of  the  hide  to  the  last  operation  of  finishing. 
Although  dry  salted  and  dry  flint  hides  may  sometimes  be 
employed  for  dressing  purposes,  there  can  be  no  doubt  that 
the  best  hides  for  this  class  of  leather  are  the  recently 
flayed  hides  as  they  come  from  the  slaughter-house.  Hides 
which  have  been  badly  flayed,  branded,  or  pitted  with 
warble  marks  should  be  rejected.  The  hides  employed  for 
harness  purposes  are  those  of  cows  and  smaller  oxen. 

Selection  of  Hides. — "  A  perfect  hide  for  dressing  pur- 
poses should  be  thoroughly  flayed,  free  from  warbles  or 
warble  marks,  of  a  close,  fine,  glossy  grain,  without  any 
scratches  or  brands,  and  well  filled  and  level  throughout. 
Now  many  hides  may  have  all  the  first  qualities,  and 
may  be  full  and  plump  at  the  back,  but  fall  away  at  the 
shoulders,  and  nothing  makes  a  more  imperfect  trace  or 
rein  if  it  is  not  of  the  same  substance  throughout.  1 
know  it  is  most  difficult  to  get  hides  with  all  the  requisites 
mentioned,  but  the  only  way  is  for  the  tanner  to  buy  as 
many  as  he  possibly  can  at  the  proper  season  of  the  year, 


224  LEATHER  MANUFACTURE. 

go  to  market  where  he  gets  the  best  selection,  and  go  over 
the  lots  or  piles  of  hides  himself,  feeling  along  the  shoul- 
ders and  neck,  and  only  purchasing  the  lots  where  the 
fewest  flat  or  thin  hides  are/'  * 

Washing  and  Cleansing. — The  hides  are  thrown  into  a 
pit  containing  clean  water,  to  remove  the  blood,  dung, 
and  dirt,  in  which  they  remain  for  twenty-four  hours. 
They  are  then  drawn,  and  the  horns  and  tail  removed, 
after  which  they  are  again  steeped  for  twenty-four  hours. 
Dried  and  salted  hides,  however,  require  a  much  longer 
soaking,  and  must  be  effectually  and  thoroughly  cleansed 
and  softened  before  going  into  the  lime.  Old  bate  liquor 
is  recommended  as  a  good  soak  for  dried  and  salted  hides 
and  kips.  In  former  days  some  of  the  Leeds  kip  tanners 
considered  this  old  soak  so  valuable  that  they  worked  it 
for  many  months  without  throwing  it  away.  The  fulling 
stocks  are  much  employed  for  the  softening  of  dried  kips, 
and  the  beating  action  of  the  stocks,  alternated  by  soaking, 
will  generally  bring  them  to  nearly  the  condition  of  fresh 
hides  in  the  course  of  a  week  or  ten  days. 

Liminfj. — The  method  recommended  by  "  an  old  Scotch 
Tanner  "  is  as  follows  :  "  The  hides  being  thoroughly 
washed  and  cleaned  in  the  water  pits,  are  drawn  up  and 
piled  one  on  the  top  of  another,  hair  upwards,  next  to 
No.  1,  or  the  weakest  lime  pit.  The  lime  liquor  in  the 
pit  must  be  plunged  with  a  plunger  to  raise  the  lime 
from  the  bottom,  the  hides  thrown  in,  two  men  working 
at  the  hides  and  two  men  carefully  laying  them  out  and 
putting  down  with  sticks.  I  allow  them  to  lie  for  twenty- 
four  hours  in  No.  1,  or  weakest  lime  pit,  and  draw  them 
next  morning,  great  care  being  taken  not  to  scratch  the 
grain  of  the  hide  with  the  hook.  Ten  hides  are  thrown 
aside  from  the  top  of  the  pack,  and  are  put  at  the  bottom. 
The  hides  are  then  put  into  No.  2  lime,  which  should 
be  a  little  stronger  than  No.  1,  spreading  them  out  as 
was  done  previously.  I  allow  them  to  lie  in  No.  2  lime 
twenty- four  hours,  then  draw  them  and  put  them  into 
No.  3  lime,  changing  ten  hides  again  from  the  top  to  the 
*  Scottish  Leather  Trader. 


HARNESS  LEATHER    TANNING.  225 

bottom  of  the  pack.  No.  3  lime  should  be  stronger  than 
No.  2,  and  so  on  in  succession,  the  last  lime  being  the 
strongest  and  newest.  I  draw  all  my  hides  every  morn- 
ing, transferring  ten  hides  from  the  top  to  the  bottom  of 
the  pack  each  time,  and  changing  them  over  to  a  stronger 
lime  till  they  come  to  the  strongest  lime,  where  they  lie, 
of  course  draining  every  morning,  till  they  are  ready  for 
unhairing.  If  after  eight  days  or  so  I  find  the  hair  not 
giving  way,  I  add  a  little  fresh-slaked  lime  to  the  liquor 
when  the  hides  are  lying  up.  It  is  impossible  to  give  the 
proper  quantity  of  lime  that  should  be  used  (owing  to  its 
variable  quality).  Every  tanner,  if  he  pays  proper  attention 
to  his  limes,  will  soon  find  this  out  and  regulate  the 
quantity  himself.  Do  not  allow  your  limes  to  get  old  or 
stale  ;  the  value  of  lime  is  not  great,  and  there  is  far 
more  to  be  lost  by  the  hide  being  kept  in  weak  old  limes 
than  in  casting  away  the  old  lime  and  making  fresh 
liquors.  This,  I  think,  is  one  of  the  causes  why  some 
tanners  never  get  proper  weight  into  their  leather.  The 
time  I  give  my  hides  is  from  ten  to  twelve  days,  when 
they  should  unhair  easily  ;  when  unhaired,  I  throw  them 
into  a  pit  of  clean  water,  to  remove  all  superfluous  lime 
that  may  be  adhering  to  them,  when  they  are  ready  for 
fleshing."  We  think  there  can  be  no  doubt  as  to  the 
danger  of  keeping  hides  for  any  length  of  time  in  ex- 
hausted or  very  weak  lime  liquors ;  and  it  is  more  than 
probable  that  limes  to  which  the  term  "  weak  "  is  applied 
frequently  contain  little  or  no  lime  in  an  active  or  caustic 
state,  from  the  fact  that  the  lime  liquors  are  constantly 
exposed  to  the  action  of  the  atmosphere,  from  which  they 
are  continually  absorbing  carbonic  acid,  converting  the 
caustic  into  carbonate  of  lime,  which  can  have  no  effect 
upon  the  hides,  while  the  liquor  not  being  caustic  would 
naturally  have  the  same  solvent  action  upon  the  gelatine  of 
the  skins  as  water,  and  would  therefore  reduce  their  weight. 
Bating. — After  liming,  unhairing,  and  fleshing,  the 
pelts  are  bated  in  a  bate  of  hen  manure,  or,  according  to 
the  practice  of  the  tanner,  they  are  treated  in  boric  or 
lactic  acid  solutions,  &c. 

Q 


226  LEATHER  MANUFACTURE. 

Tanning. — The  pelts  are  treated  in  the  handlers  in  the 
same  way  as  those  intended  for  sole  leather,  except  that 
they  are  not  kept  in  the  old  and  sour  liquors  for  a 
lengthened  period,  but  merely  sufficiently  long  to  "  clear 
the  grain/'  as  it  is  termed.  They  are  next  treated  in 
weak  sweet  liquors  of  progressive  strength,  the  liquors 
being  returned  to  the  leaches  to  be  strengthened,  as  usual. 
The  strongest  liquors  in  the  handlers  should  not  exceed 
from  10°  to  12°.  The  hides  are  treated  in  the  handlers 
for  about  a  month  or  six  weeks,  being  worked  in  a  round, 
after  which  they  are  placed  in  pits  containing  stronger 
ooze  and  finely  ground  oak-bark,  being  worked  in  a 
round  as  before,  for  two  or  three  months,  after  which 
they  are  stratified  with  ground  oak-bark  in  the  layers, 
and  treated  with  a  still  stronger  ooze.  After  about  six 
weeks  the  hides  are  taken  out,  and  again  laid  down  with 
interposed  layers  of  ground  bark  and  strong  ooze,  and  in 
these  pits  they  remain  for  about  two  months,  the  process 
being  repeated  once  or  twice  more,  until  the  tanning  is 
complete. 

'  Crop  Leather. — Crop  leather,  now  almost  extinct,  in- 
cluded the  leather  prepared  from  the  hides  of  cows  and 
small  oxen,  the  former  (provided  the  cow  has  not  calved) 
yielding  the  strongest  and  toughest  leather  of  the  two. 
As  a  general  rule  the  stoutest  and  most  compact  or  com- 
pressed leather  (from  ox  hides)  is  used  for  sole  leather,  but 
not  unfrequently  leather  made  from  crop  hides  was  devoted 
to  this  purpose,  without  being  rolled  and  condensed  by  the 
tanner,  as  in  the  case  of  butts.  The  lighter  cow  hides  are 
used  for  the  uppers  of  stout  shoes  and  boots,  inner  soles, 
and  also  for  water-boots,  and  other  purposes.  The  hides 
of  young  oxen,  being  deficient  in  firmness  and  thickness, 
are  chiefly  used  for  belt  leather.  In  the  treatment  of  crop 
hides,  they  are  first  submitted  to  the  usual  preliminary 
operations,  and  are  then  placed  in  the  lime  pits  until 
ready  for  unhairing,  which  in  summer  is  usually  in  about 
eight  days,  and  in  winter  from  ten  to  fourteen  days  ;  they 
are  then"  sent  to  the  beam-house,  where,  after  unhairing, 
they  are  fleshed  with  great  care,  being  frequently  rinsed 


HARNESS  LEATHER   TANNING.  227 

each  time,  in  running  water  if  practicable,  to  remove  the 
lime  as  far  as  possible.  The  hides  intended  for  uppers 
require  at  least  four  or  five  rinsings,  while  those  which 
are  to  be  used  for  sole  leather  require  but  two  rinsings. 
They  are  next  raised,  either  by  immersion  in  dilute  sul- 
phuric or  hydrochloric  acid,  according  to  the  tanner's 
practice  ;  and  they  are  then  placed  in  the  handlers,  in 
weak  ooze  at  first,  in  which  they  are  handled  daily  in 
the  same  way  as  butts,  and  are  afterwards  treated  in 
stronger  ooze,  and  handled  as  before  during  a  period  of 
four  or  five  weeks.  They  are  next  put  into  the  layers, 
in  which  they  are  carefully  spread  out,  with  alternate 
layers  of  finely  ground  oak-bark;  the  pit  is  then  filled 
up  with  ooze.  At  the  end  of  about  six  weeks  they  are 
taken  out  and  subjected  to  a  fresh  change  of  bark  and 
ooze,  this  being  repeated  once  or  twice  more  until  the  hides 
are  perfectly  tanned. 


CHAPTER  XVIII. 

AMERICAN  TANNING. 

Cold  Sweating  of  Hides. — Sweat  Pits. — Treatment  of  Hides  in  the  Sweat- 
pits. — Treatment  of  Hides  after  Sweating;. — Liming. — Unh airing  by 
Prof.  Lupkin's  Process. — Beam  Work. — Trimming  or  Rounding. — 
Grinding  the  Bark. — Leaching. — The  "  Press"  Leach. — Raising  with 
Vitriol.— Handling.— The  Rocker  Handler.— The  Layers. 

WHILE  our  American  cousins  freely  and  generously 
acknowledge  the  excellence  of  English  tanned  leather, 
and  highly  compliment  our  manufacturers  upon  the  care 
and  economy  with  which  they  conduct  their  various 
operations,  there  is  much  in  the  Transatlantic  system  of 
tanning  which  deserves  and  must  command  attention. 
If,  however,  our  great  American  competitors  were  as 
silent  upon  the  subject  of  which  we  are  treating  as  are 
our  own  countrymen — with  few  exceptions — we  should 
have  but  little  to  communicate  as  to  the  modus  operand* 
adopted  in  the  United  States.  The  whole  fraternity  of 
tanners,  however,  both  at  home  and  abroad,  are  indebted 
to  Mr.  Jackson  S.  Schultz,  an  eminent  American  tanner, 
for  a  very  clear  and  practical  book  on  the  manufacture 
of  leather*  as  conducted  in  the  States,  being  the  substance 
of  a  long  series  of  valuable  papers  contributed  by  him  to 
the  Boston  Shoe  and  Leather  Reporter.  Independent  of 
the  great  service  which  these  writings  must  have  rendered 
his  own  countrymen,  there  is  a  great  deal  of  information 
conveyed  by  the  pen  of  this  astute  writer  which  should 
be  read  by  all  who  follow  the  art  of  tanning,  even  though 
they  treat  specially  of  the  method  adopted  in  the  United 
States. 

*  "  Leather  Manufacture."    By  Jackson  S.  Schultz. 


AMERICAN  TANNING.  229 


"We  now  purpose  giving,  as  briefly  as  possible,  a 
of  the  American  system  of  tanning,  as  explained  by  Mr. 
Schultz,  but  must  refer  the  reader  to  his  own  admirable 
work  for  more  complete  information. 

Cold  Sweating  of  Hides.  —  While  in  Great  Britain 
sheep  skins  are  freed  from  their  wool  by  "  steam  sweat," 
as  it  is  called,  in  the  United  States  a  system  of  cold 
sweating  is  adopted  for  heavy  hides  which  at  present 
is  chiefly  confined  to  that  country.  Schultz  says,  "  It  is 
now  demonstrated  that  a  wooden,  brick,  or  stone  structure, 
on  the  top  of  the  ground,  can  be  so  completely  protected 
from  the  rays  of  the  sun  and  other  atmospheric  influences 
as  to  make  a  good  sweat-pit.  The  ice  companies  have 
adopted  surface  structures  of  wood  filled  in  with  sawdust, 
tan-bark,  or  charcoal  between  the  outside  clapboards  and 
the  inner  linings  of  their  buildings,  and  this  same  form 
of  structure  will  make  a  most  serviceable  tanner's  sweat- 
pit.  But  since  the  sweat-pit  is  subject  to  greater  changes 
of  atmosphere  than  the  ice-house,  it  is  desirable  that  the 
inner  lining  of  the  sweat-pit  should  be  of  a  more  endur- 
ing substance  than  wood.  The  damp  but  warm  atmo- 
sphere of  tanners'  sweat  decomposes  the  fibres  of  the 
wood  very  fast.  On  account  of  this  liability  to  decay,  if 
for  no  other  reason,  the  sweat-pits  of  the  tanners  should 
be  constructed  of  stone  or  brick. 

Sweat  Pits.  —  "The  structures  may  be  wholly  above 
ground,  and  should  be  so  placed  that  a  wheelbarrow  may 
be  run  from  the  floor  of  the  beam  house  to  the  main  passage- 
way of  the  sweat-pit.  These  passages  should  be  wide  —  not 
less  than  6  to  8  feet  —  and  be  so  thoroughly  lighted  both 
from  top  and  ends  as  to  make  their  passage  by  workmen 
and  employes  both  easy  and  agreeable.  The  height  of  this 
main  passage-way  should  extend  above  the  surrounding 
pits,  and  by  this  '  lantern  '  construction  both  light  and 
air  can  be  secured  in  the  passage-way  below.  The  pits 
themselves  should  extend  from  both  sides  of  this  main 
passage,  and  be  connected  with  folding  doors  wide  enough, 
when  fully  open,  to  admit  a  wheelbarrow." 

Each  of  such  pits  must  be  large  enough  to  hold  one 


230  LEATHER  MANUFACTURE. 

pack  of  hides,  and  high,  enough  to  allow  the  suspension 
of  a  side  doubled,  with  2  feet  clear  aboye  and  1  foot 
below  the  hooks.  The  pits  should  be  about  8  feet  wide, 
giving  space  for  two  tiers  of  sides  and  gangway  for  the 
workmen.  The  pits  should  be  so  constructed  that  light 
may  enter  sufficient  to  allow  a  close  examination  of  the 
hides  without  the  employment  of  a  lamp,  and  should  be 
kept  in  such  a  cleanly  condition  that  any  person  could 
enter  the  pit  without  soiling  his  clothes.  Mr.  Schultz 
lays  great  stress  on  this  point.  The  temperature  of  the 
pits  is  kept  under  control  by  steam  and  cold  water,  which 
are  admitted  through  the  main  passage  by  means  of 
pipes.  "A  properly  constructed  pit  should  have  a  false 
bottom,  under  which  the  steam  may  be  forced,  to  find  its 
way,  in  condensed  spray,  up  through  the  suspended  sides. 
This  process  will  adequately  warm  the  pit.  When  too 
warm,  cold  water  may  be  thrown  from  the  mouth  of  a 
sprinkler  over  the  whole  surface,  and  thus,  in  a  few 
moments,  cool  the  whole  space,  and  leave  a  desirably 
moist  atmosphere."  The  temperature  should  be  main- 
tained at  from  60°  to  70°,  with  globules  of  moisture  rest- 
ing on  all  parts  of  the  suspended  hides,  which  eventually 
collect  and  drop  from  points  of  the  hair. 

The  sweat-pits  are  covered  by  stout  timber,  above 
which  is  a  layer  of  earth  about  2  feet  thick,  which  is  kept 
well  watered,  so  as  to  protect  the  interior  from  the  heat 
of  the  sun's  rays.  The  sides  of  the  pits  may  be  protected 
with  the  same  object,  either  by  means  of  earth  or  spent 
tan.  With  pits  so  constructed  hides  may  be  properly 
"  sweated "  in  from  three  to  seven  days — usually  about 
four  or  five  if  the  hides  are  in  proper  condition.  The 
cold  sweating  process  is,  however,  chiefly  adopted  for  dry 
"flint  hides."  Before  submitting  the  dry  hides  to  the 
sweating  process,  they  require  to  be  softened  or  brought 
to  the  condition  of  green  hides  by  the  usual  methods  of 
soaking,  beating,  &c. 

Treatment  of  the  Hides  in  the  Sweat-pits. — The 
hides  should  be  hung  on  the  racks  by  tenter-hooks,  being 
suspended  either  from  the  shoulder  or  from  the  butt,  but 


AMERICAN  TANNING.  23* 

whichever  method  is  adopted  the  same  should  be  applied 
to  all,  so  as  to  ensure  uniformity  of  action  in  the  sweat- 
pits.  Since  the  sweating  is  more  rapid  above  than  below, 
and  as  the  thicker  parts  of  the  hide  will  resist  the  action 
of  the  sweating  longer  than  the  thinner  parts,  it  would  be 
better  if  the  pates  and  butts  could  be  suspended  higher 
than  the  bellies  and  shoulders ;  but  since  this  would  in- 
volve considerable  difficulty,  the  same  result  is  attained  by 
changing  the  position  of  the  hides  after  three  or  four  days, 
when  the  process  of  sweating  will  have  advanced  con- 
siderably. This  operation  of  "assorting  out,"  as  it  is 
termed,  requires  great  care  on  the  part  of  the  workmen, 
since  upon  this  in  a  great  measure  depends  the  success  of 
the  operation.  This  care  is  specially  necessary  at  this 
stage,  since  no  two  hides,  however  uniform  in  character, 
will  sweat  exactly  alike.  "  No  hour  in  the  whole  day," 
says  Mr.  Schultz,  "should  be  without  a  visit  to  the 
advanced  sweats.  When  a  few  sides  give  indication  of 
*  coming '  prematurely,  before  their  proper  time,  they 
should  be  dropped  to  the  bottom  of  the  pit,  and  allowed 
to  lay  in  piles  until  their  less  advanced  companions  catch 
up  in  the  process  of  decomposition." 

Treatment  of  Hides  after  Sweating. — The  sweated 
hides  are  next  thrown  into  the  mill  for  a  few  moments,  to 
wash  away  the  dirt  and  "  slime,"  and  to  rub  as  much  of 
the  hair  off  as  can  be  removed  by  such  means.  In  respect 
of  this  operation,  however,  Mr.  Schultz  says :  "  During 
this  short  and  damaging  process  two  things  happen — 

1.  The  loose  hair  is  fulled  into  the  flesh  so  firmly  as  to 
make  it  difficult  to  remove  afterwards  on  the  beam ;   and 

2.  To  pound  out  much  of  the  gelatine  of  the  hide,  which 
at  this  period  is  almost  in  a  soluble  condition,   and  will 
part  from  its  proper  lodgment  in  the  fibre  almost  as  freely 
as  the  slime  and  dirt  with  which  the  surfaces  are  supposed 
to  abound.     Indeed,  much  of  the  substance  that  is  regarded 
as  '  slime '  and  '  dirt '  is  the  gelatine,  which,  when  com- 
bined with    tannin,    goes  to    make  leather."      He  very 
properly   condemns   the    practice   of   fulling   or   milling 
the  hides  after  sweating,  which  must  reduce  their  weight 


232  LEATHER  MANUFACTURE. 

considerably,  besides  disturbing  the  delicate  structure  of 
the  hide  itself.  The  system  which  many  intelligent 
tanners  of  the  States  have  found  most  practical  is  to 
throw  the  hides  as  they  are  removed  from  the  sweat-pits 
into  weak  lime  liquor  for  a  short  time,  by  which  a  slight 
plumping  or  swelling  of  the  hides  takes  place,  and  the 
slimy  condition  disappears,  while  the  hair  does  not  attach 
itself  to  the  flesh  as  in  the  former  treatment.  He  advo- 
cates part  liming  and  part  sweating  as  a  good  method  of 
loosening  the  hair. 

"  There  can  be  no  doubt,"  he  says,  "  that  our  American 
system  of  cold  sweating  is  calculated,  beyond  any  other 
known  method,  to  make  a  firm,  compact  fibre  when 
properly  used,  and  besides  it  is  specially  adapted  to  the 
preparation  of  the  dry  hides  of  our  continent.  It  only 
remains  for  me  to  say  a  word  on  the  subject  of  '  grease  ' 
and  '  salt/  as  among  the  hindrances  which  affect  and 
control  the  sweating  of  hides.  All  sweat  tanners  fully 
understand  that  the  salt  (if  the  hide  is  salted  or  pickled) 
must  be  fully  soaked  out  before  the  hide  will  sweat. 
From  this,  among  other  circumstances,  is  deduced  the 
inference  that  this  process  is  a  decomposing  one,  for, 
so  long  as  the  hide  is  held  (cured),  from  the  presence  of 
salt,  carbolic  acid,  and  other  tanning  ingredients,  the 
sweats  will  not  operate  on  the  hide.  So,  too,  if  this  is 
covered  with  grease,  as  many  of  our  Western  and  Cali- 
fornian  hides  are,  it  will  not  sweat  evenly,  owing  to  the 
presence  of  the  grease  on  some  portions  more  than  others." 

Liming. — The  method  of  preparing  the  lime  liquors  in 
America  is  in  many  respects  different  from  that  generally 
adopted  in  this  country,  one  point  of  difference  being  that 
loss  lime  is  employed  than  is  usual  here.  After  recom- 
mending that  the  lime  should  be  kept  in  dry  and  confined 
apartments,  where  neither  moisture  nor  air  can  reach  it, 
Schultz  recommends  that  a  half  hogshead  should  be 
placed  near  the  lime- vat  which  has  to  be  replenished.  For 
a  pack  of  120  to  140  hides  about  a  bushel  of  lime  is  put 
into  the  tub,  and  one  or  two  pails  of  water  poured  on ;  the 
vessel  is  then  to  be  covered  with  thick  canvas.  As  the 


AMERICAN  TANNING.  233 

water  is  absorbed  more  is  added  if  required,  but  our  own 
experience  in  the  slaking  of  lime  teaches  us  that  a  much 
less  quantity  than  two  pails  of  water  would  be  sufficient 
to  slaken  a  bushel  of  lime.  It  is  always  a  great  advantage 
to  cover  up  the  vessel  in  which  lime  is  slaked,  since  by  so 
doing  much  less  water  may  be  used,  and  the  confined 
steam  aids  the  slaking  greatly. 

Whereas  in  this  country  it  is  usual  to  put  a  considerable 
quantity  of  lime  in  the  pits,  Mr.  Schultz  says,  "  Nothing 
but  pure  limewater  should  ever  be  allowed  to  enter  the  vat. 
This  will  not  only  render  frequent  '  cleaning  out '  unne- 
cessary, but  will  save  the  flesher's  edge,  and  also  save  time 
in  many  respects/'  He  allows  three  or  four  days  only  for 
the  liming,  and  in  this  time  "  the  lime  will  not  improperly 
fill  the  hide,  and  when  unhaired  it  may  be  speedily  reduced 
to  a  proper  condition.  The  reduction  (depilation)  will  be 
well  begun  by  throwing  the  hides  or  sides  into  a  wheel 
(drum),  and  with  a  flow  of  warm  water  turned  on  run  them 
for  ten  minutes.  The  advantage  of  warm  instead  of  cold 
water  is  very  marked,  and  may  at  this  stage  of  the  process 
be  freely  used  with  safety.  It  is  always  safe  to  use  on 
hides  filled  with  lime  heat  to  the  extent  of  110°.  .  .  This 
rinsing  process  will  remove  the  greater  portion  of  the 
lime,  and  will  ordinarily  prepare  the  hides  for  the  liquor." 
Some  tanners,  however,  to  get  rid  of  the  lime  more  effec- 
tually, use  hens'  dung  or  sour  bran  liquor.  This  latter 
precaution,  however,  is  not  considered  necessary  for  sole 
leather,  while  for  upper  leather,  it  is  necessary  that  the 
skins  should  be  as  free  as  possible  from  lime  before  they 
go  into  the  handlers.  The  sour  liquors  of  the  handlers 
are  deemed  sufficiently  active  to  remove  the  lime  from 
heavy  hides,  provided  the  fibre  has  not  been  unduly 
strained  in  the  beam  house. 

Unhairing  by  Prof.  Lupkin's  Process. — By  this  method 
one  tanner  in  New  Jersey  prepared  not  less  than  50,000 
hides  annually  with  great  success.  His  packs  were  made 
up  of  about  50  hides  each,  either  cured,  green,  salted,  or 
dry  Buenos  Ayres  or  Rio  Grande.  The  green  weighed 
about  50  Ibs.  and  the  dry  about  20  Ibs.  For  such  a  pack 


234  LEATHER  MANUFACTURE. 

80  Ibs.  of  lime  would  be  slaked,  but  the  lime  was  not  watered 
after  slaking,  as  usual,  but  was  left  in  the  condition  of  a 
thick  paste.  A  small  portion  of  this  was  kneaded  thoroughly 
with  10  Ibs.  each  of  soda  ash  and  powdered  sulphur.  When 
these  substances  were  well  mixed,  they  were  thrown  into 
the  tub  in  which  the  bulk  of  the  lime  reposed,  and  while 
this  was  still  warm ;  the  whole  were  then  thoroughly 
mixed,  and  the  tub  then  filled  with  lime  liquor  and  the 
whole  well  stirred.  When  this  was  done,  the  mixture  was 
poured  into  the  vat,  and  the  whole  thoroughly  plunged. 
No  more  liquor  was  employed  than  would  be  sufficient  to 
cover  the  100  hides  when  thrown  in.  The  lime  was  kept 
up  to  summer  heat  by  the  application  of  steam.  The 
handling  was  performed  once  or  twice  a  day,  if  thrown 
into  the  vat  as  usual.  Mr.  Schultz  says,  "  There  is  no 
doubt  that  it  is  a  good  method  of  unhairing  for  any 
hides  or  skins,  and  when  a  soft  and  smooth  grain  is 
desirable  it  is  a  valuable  improvement.  Of  course,  it 
is  slightly  more  expensive  than  pure  lime,  and,  for  this 
reason,  has  not  found  general  favour."  The  soda  ash  in 
this  process  combines  with  a  portion  of  the  lime,  forming 
caustic  soda. 

By  another  process  the  hides,  after  the  usual  preparation, 
are  thrown  into  a  strong  lime  for  8  or  10  hours,  when  they 
are  taken  o  ut  and  immersed  in  water  up  to  1 1 1  °.  The  warm 
water  soaks,  softens,  and  swells  the  roots  of  the  hair,  and 
has  much  the  effect  of  the  "  scalding "  applied  to  hogs. 
"  So  little  lime  permeates  the  inner  fibre,  that,  after  a  slight 
wheeling,  the  hides  may  be  thrown  into  cold  water  and 
allowed  to  cool  and  plump  preparatory  to  taking  their  place 
in  the  handlers.  The  process  is  strongly  commended  for 
sole  leather,  particularly  where  great  firmness  of  fibre  is 
desired.  The  tanner  who  tries  this  method  must  be  satisfied 
if  he  gets  twenty  to  thirty  sides  per  man,  unhaired  and 
fully  completed  for  the  liquor,  per  day."  Instead  of  the 
usual  handling  in  the  lime,  the  hides  may  be  "  strung  " 
together,  and  reeled  over  from  one  pit  to  another  by  means 
of  the  hand-reel,  Fig.  43.  This  simple  contrivance  for 
removing  hides  from  one  pit  to  another,  as  a  substitute 


AMERICAN  TANNING. 


235 


for  the  usual  handling,  should  command  attention.  In 
speaking  of  its  capabilities  Schultz  says,  "The  facility 
with  which  packs  may  be  thus  transferred  from  one  pit 
to  another  commends  this  skeleton  reel  to  all  tanners.  It 
is  safe  to  estimate  the  performance  of  this  machine  with 
two  men  as  equal  to  that  of  six  men  by  the  old  process. 
Besides,  it  does  not  require  either  man  to  stoop  to  his 
work,  and  the  labour  is  therefore  easier.  The  stand  and 


Fig.  43. 

skeleton  drum  should  be  made  of  as  light  material  as 
possible,  so  that  its  transfer  from  one  vat  to  another  may 
be  effected  by  two  men  with  ease.  As  there  need  be  but 
one  of  these  reels  in  an  ordinary  sized  tannery,  the  tanner 
can  well  afford  to  have  the  frame,  drum,  and  bearings 
made  of  substantial  but  light  materials,  well  adjusted  in 
all  parts,  even  with  brass  bearings.  Two  men  can  shift 
10,000  in  ten  hours.  The  hides  may  be  tied  together  with 
strings." 

Beam  Work — "No  amount  of  labour  and  care,"  says  Mr. 
Schultz,  "  in  the  after  processes  can  atone  for  neglect  in 
this  department.  The  flesh  should  all  be  removed,  and  the 


236  LEATHER  MANUFACTURE. 

natural  structure  of  the  hide  (pelt)  should  not  be  disturbed 
or  even  touched  with  the  edge  of  the  flesher.*.  .  .  The 
usual  flesher  and  half-round  beam  are  too  familiar  to  the 
tanner  to  require  notice  in  this  connection,  but  within  a  few 
years  the  French  and  German  beam-knife  has  been  intro- 
duced, and  received  with  general  favour.  This  knife  is  about 
one-third  larger  than  ours,  and  is  not  more  than  two  inches 
wide  ;  the  material  is  the  best  steel,  and  is  not  more  than 
a  quarter  of  an  inch  in  thickness  in  the  rib  or  centre.  The 
blade  is  so  supple  that  the  handles  can  almost  be  brought 
together.  It  is  claimed  for  this  knife  that  by  its  supple 
nature  it  bends  around  the  rounded  convex  form  of  the 
beam,  and  makes  a  natter  cut  on  the  flesh  of  the  side,  less 
concave  than  a  stiff,  straight- edged  flesher  cutting  on  an 
oval  or  convex  surface.  To  this  extent  the  new  knife  cer- 
tainly does  present  advantages,  and  may  be  safely  trusted 
to  do  good  work  in  skilled  hands/' 

Trimming  or  Bounding. — This  author  speaks  highly 
of  the  economy  and  judgment  displayed  by  the  English 
tanners  in  their  method  of  rounding,  and  gives  the  following 
reasons  why  this  method  is  adopted : — 1st.  The  shoulders 
and  offal  are  much  thinner  than  the  butts,  and,  therefore, 
tan  in  a  shorter  time.  2nd.  The  offal  being  used  where  a 
tough  fibre  is  required,  slack,  or  at  most  a  full  tanning, 
is  all  that  is  required.  3rd.  The  boot  and  shoe  manu- 
facturers, not  only  of  Europe  but  of  America,  have  so 
classified  their  work  that  those  who  use  butt  leather 
largely  do  not  require  so  much  "  inner  soleing "  and 
"welting"  as  would  come  from  the  bellies  and  shoulders 
of  these  out-soles. 

Mr.  Schultz  says,  "  It  is  probably  true  that  the  population 
of  Great  Britain  is  better  and  more  economically  shod  than 
any  other  people  in  the  world.  A  portion  of  the  economy 
is  due,  however,  to  iron  rather  than  leather. f  Much  of  the 
economy  here  conceded  arises  from  their  method  of  trim- 

*  Fleshing-knif9. 

t  This  remark  is  specially  applicable  to  the  present  time,  when  metal 
sole  and  heel  "protectors'"'  are  so  extensively  applied  by  the  public 
themselves. 


AMERICAN  TANNING.  237 

ming  and  rounding  their  hides  and  skins.  That  which 
belongs  to  the  glue-maker  never  goes  beyond  the  beam 
house  in  any  tannery  in  Europe." 

Grinding  the  Bark. — In  the  United  States  the  spent 
tan  is  largely  used  as  fuel  by  the  tanner  for  the  generation 
of  steam  for  his  grinding-mills,  for  the  leaching  of  bark, 
and  other  purposes,  and  to  a  great  extent  has  supplanted 
the  use  of  all  other  fuel,  and  even  water-power.  "  So 
absolutely  inexpensive  is  this  substitute,"  says  Mr.  Schultz, 
"  that  power  and  heat  may  be  used  without  stint  and  limit 
in  the  manipulations  of  all  our  modern  sole  leather 
tanneries.  .  .  .  The  fact,  then,  stands  conceded  that  the 
wet  spent  tan  from  an  ordinary  sole  leather  tannery  will 
give  ample  power  to  grind  all  the  bark  and  heat  all 
the  liquors  required."  He  writes  strongly  against  mills 
which  grind  at  high  speed,  and  doubts  whether  a  motion 
over  80  revolutions  per  minute  is  either  profitable  or 
effective.  The  benefits  which  may  be  derived  by  adopting 
a  higher  speed  in  nowise  overbalance  the  defects  in 
grinding  and  danger  of  fire  from  excessive  friction.  "  A 
quick  motion  has  the  effect  to  '  throw  up  '  and  '  back '  the 
bark,  rather  than  take  it  in  and  pass  it  through  the  grind- 
ing surfaces,  as  a  slower  motion  will."  He  recommends  80 
revolutions  on  a  small  and  70  revolutions  on  a  large  mill 
as  the  proper  motion. 

Speaking  of  the  American  methods  of  grinding  and 
leaching,  Schultz  says  it  is  estimated  that  from  7  to  10 
per  cent,  of  tannin  is  left  in  the  bark,  and  it  is  doubtful 
if  any  of  their  methods  will  take  out  the  remainder  profit- 
ably. He  says,  moreover,  that  "  the  time  may  come  when 
hemlock  and  oak-bark  (the  chief  materials  used  in  the 
States)  will  be  so  scarce  and  dear  as  to  necessitate  other 
means  than  grinding  and  leaching  for  extracting  all  the 
strength  from  the  bark."  It  seems  strange  that  when  our 
American  cousins  are  so  ingeniously  utilising  what  they 
consider  their  "  waste  "  tan,  that  they  are  wasting*  in  a 
true  sense  from  7  to  10  per  cent,  of  material. 

*  Chemists  are  now  employed  in  all  large  American  tanneries,  and  all 
mateiials  much  more  thoroughly  extracted  under  their  direction. — ED. 
Fifth  Edition. 


238  LEATHER  MANUFACTURE. 

Leaching. — "  The  full  and  perfect  extraction  of  all  the 
tannin  from  the  bark  is  not  only  desirable,  but  it  is  of 
primary  importance  ;  it  is  equally  essential,  however,  that 
this  subtle  elixir  should  be  extracted  without  deterioration 
or  injury.  It  is  found  in  practice  not  at  all  difficult  to 
wash  out  all  the  extractive  or  soluble  matter  from  the 
bark ;  but  to  separate  and  take  out  the  greatest  amount  of 
tannin,  leaving  the  largest  portion  of  colouring  and 
resinous  matter  behind,  is  quite  a  different  matter,  and 
one  which  has  taxed  the  efforts  of  our  best  tanners.  The 
system  of  leaching  which  will  enable  the  tanner  to  control 
and  separate  these  qualities  is,  in  my  judgment,  the 
system  to  be  most  commended."  In  this  view  Mr.  Schultz 
does  not  appear  to  be  supported  by  some  of  the  largest 
American  tanners,  as  he  frankly  admits,  but  he  believes 
that  their  theory  is  based  on  the  assumption  that  colouring 
matter,  entering  into  the  substance  of  the  hide,  gives 
weight ;  and  that  also  the  resinous  matter  in  some  myste- 
rious way  attaches  itself  to  the  leather,  defying  the  action 
of  the  scrubber  to  wash  it  off.  To  this  theory  he  strongly 
objects,  and  asserts  that  "  tannin,  and  not  colouring  or 
resinous  matter,  enters  the  fibre  and  gives  weight."  But  if 
Davy's  well-known  theory  be  accepted,  does  not  the  colour- 
ing matter  (setting  aside  the  resinous  matter)  enter  into  the 
substance  of  the  hide  with  the  vegetable  extractive,  which 
forms  an  essential  ingredient  in  the  formation  of  leather  ? 

The  system  of  leaching  in  America,  by  the  application 
of  heat,  appears  to  be  open  to  objection,  since  the  chief 
tanning  agent,  hemlock-bark,  yields  not  only  an  objection- 
able colour,  which  is  more  freely  extracted  in  hot  than  in 
cooler  liquors,  but  also  resinous  matter,  which  can  play  no 
useful  part  in  tanning.  "  The  union-crop  leather  tanners," 
Mr.  Schultz  remarks,  "  have  learned  to  appreciate  the  value 
of  moderate  instead  of  extreme  heat,  and  when  better 
methods  of  grinding  and  screening  the  bark  shall  be  appre- 
ciated at  their  full  value,  then  I  assume  that  even  less  heat 
than  at  present  will  be  employed  by  them,  and  the  more 
nearly  summer-heat  (60°*)  is  adhered  to,  in  the  head  leach, 
*  The  summer-heat  in  this  country  is  78°  Fahr. 


AMERICAN  TANNING.  239 

the  more  modified  and  controllable  will  be  the  colour." 
Since  it  is  so  well  known  that  tannin  is  freely  soluble  in 
cold  water,  and  that  colouring  matter  is  more  readily 
extracted  from  bark  by  hot  than  by  cold  water,  it  must 
certainly  be  erroneous,  especially  if  the  colouring  matter 
is  of  an  objectionable  character,  to  use  heat  for  the  leaching 
of  this  otherwise  most  useful  bark,  hemlock.  Mr.  James 
Cleaver,  an  American  tanner  of  repute,  proved  that  he  could 
make  from  190  to  200  Ibs.  of  leather  with  one  ton  of  bark, 
never  employing  a  higher  temperature  for  his  head  leach 
than  that  of  summer-heat,  except  in  winter. 

Of  the  several  systems  of  leaching  adopted  in  America, 
we  may  select  the  following : — 

The""  Press  "  Leach. — The  number  of  leaches  in  a  set 
(or  round)  should  correspond  with  the  number  of  days  in 
the  week.  By  this  method  one  new  leach  is  filled  in  each 
round  every  day  in  the  week,  but  if  more  than  one  leach 
is  required  for  the  day's  work,  then  the  sets  of  leaches 
should  be  multiplied  rather  than  disturb  the  order  of  the 
round.  This  arrangement  gives  at  least  five  days  for  the 
leaching  of  all  the  bark,  which  is  fully  time  enough.  It 
is  strongly  recommended  not  to  break  the  round,  which 
only  leads  to  confusion  and  waste.  As  to  when  and  where 
heat  may  be  applied,  Schultz  says,  "  Under  no  circum- 
stances is  heat  to  be  applied  to  any  other  than  the  back  or 
weakest  leach.  This  will  bring  the  strong  liquor  of  the 
set  on  the  head  leach  comparatively  cold,  or  at  most 
summer-heat.  This  course  will  take  all  the  liquors  in  the 
yard  in  a  proper  condition  to  go  upon  the  leather  without 
coolers  or  waiting.  It  will  leave  behind  much  of  the 
colouring  and  resinous  matter,  and  send  forward  a  pure 
tan  liquor  free  from  all  sediment  and  impurities." 

The  principle  on  which  the  "press  leach  "  works  is  thus 
described:  "Warm  water  or  liquor  is  more  expanded, 
and  consequently  lighter  than  cold.  Strong  liquor  is 
heavier  than  weak.  Now  if  we  put  the  two  light  condi- 
tions together,  viz.,  hot  and  weak,  and  place  them  on  top 
of  the  heavy  and  cold  liquor,  they  will  remain  separate 
for  all  the  time,  or  so  long  as  these  conditions  are  main- 


240  LEATHER  MANUFACTURE. 

tained.  A  simple  experiment  with  water  and  tan  liquor 
in  a  tumbler  will  demonstrate  this  practical  result.  "Weak 
tan  liquor  will  stand  all  day  on  the  top  of  strong  and 
heavy  liquor,  if  not  agitated.  Now  if  to  the  weak  liquor 
we  add  heat,  the  separation  will  be  still  more  marked.  A 
tumbler  half  filled  with  weak  and  warm  liquor  may  be 
forced  out  of  the  top  by  gently  inserting  strong  and  cold 
liquor  underneath  by  means  of  a  pipe.  The  action  of 
these  bodies,  if  the  experiment  is  carefully  made,  will 
satisfy  any  one  that  the  system  of  press  leaching  can  be 
carried  on  without  mixing  the  liquors  on  their  passage,  if 
the  system  recommended  be  followed."  In  other  words, 
it  is  a  question  of  gravity ;  the  heavier  liquid,  or  that 
which  is  richest  in  tannin,  will  form  the  lower  stratum, 
and  the  weak  the  upper  stratum ;  and  if  strong  cold 
liquor  were  introduced  from  above,  through  a  funnel  con- 
nected to  a  long  tube,  the  end  of  which  reached  to  the 
bottom  of  the  vat,  the  weaker  liquor  would  gradually  rise 
to  the  surface. 

In  working  the  press  leaches,  each  of  the  six  leaches 
is  filled  at  all  times  from  two-thirds  to  three-fourths 
with  bark,  and  stands  covered  with  liquor  varying  in 
strength  with  the  strength  of  bark  in  each.  "Let  us  sup- 
pose," says  Schultz,  "that  the  head  leach  has  just  been  filled 
with  fresh- ground  tan ;  the  last  or  back  leach  is  filled  with 
spent  tan  ready  to  pitch,  and  the  intermediate  four  leaches 
are  divided  into  both,  as  to  strength  of  liquor  and  age  of 
bark,  from  these  two  points.  No  liquor  is  sent  into  the 
yard  except  from  the  top  of  the  head  leach,  and  where 
very  strong  liquors  are  needed,  only  one  liquor  is  so  sent 
from  each  head  leach,  so  that  the  accumulated  strength  of 
all  the  bark  in  one  leach  is  concentrated  in  this  one  liquor. 
If  a  less  degree  of  strength  is  required,  then  two  runs 
may  be  taken  off,  and  in  exceptional  cases,  even  three  or 
four.  The  liquor  thus  sent  into  the  yard  is  not  returned 
until  the  strength  is  taken  from  it,  and  it  is  either  sent  off 
into  the  stream  as  worthless,  or  sent  back  to  the  back 
leach,  after  passing  through  the  heater,  and  heated  up  to 
100°  or  120°.  I  shall  insist  that  the  spent  tan  liquor, 


AMERICAN  TANNING.  241 

which  is  accumulated  acid  (gallic),  shall  go  lack  for  sole 
leather,  and  shall  go  off  into  the  stream  if  light  leather, 
such  as  calf,  kip,  or  even  harness,  is  to  be  tanned." 

The  usual  practice  in  working  the  leaches  is  to  run  the 
strongest  and  newest  liquor  direct  from  the  leaches  upon 
the  head  packs  on  the  last  layer.  These  liquors  should 
stand  at  fully  30°  by  barkometer.  After  thirty  days'  use 
they  will  be  reduced  to  24°,  a  portion  of  which  indicated 
strength  will  be  "  acid."  Twenty  days'  further  use  on  the 
third  layer  will  reduce  the  strength  to  18°,  and  so  on  until 
the  liquors  will  be  nearly  exhausted  and  contain  little  else 
than  acid.  These  liquors  are  put  on  the  first  layers,  or 
run  into  the  handlers  to  be  more  fully  exhausted.  The 
liquors  are  run  from  the  leaches  by  covered  and  enclosed 
wooden  tubes  or  bored-out  logs.  Mr.  Schultz  speaks 
strongly  against  the  practice,  even  if  accidental,  of  allowing 
warm  liquors  to  come  in  contact  with  half -tanned  or  green 
hides  which  have  been  sweated,  especially  in  warm 
weather,  as  decomposition  and  injury  are  sure  to  result. 

Raising  with  Vitriol. — The  practice  of  the  American 
tanners  with  regard  to  the  employment  of  sulphuric  acid 
(oil  of  vitriol)  for  raising  the  pelt  is  variable.  While 
some  pass  the  sides  through  the  handlers  before  introducing 
them  into  the  acid  liquor,  others  use  the  acid  first  and 
colour  them  afterwards ;  other  tanners,  again,  add  the  acid 
to  their  handler  liquors,  by  which  they  plump  and  colour 
the  pelts  at  the  same  time,  and  when  this  method  is 
adopted  the  strength  of  the  liquor  is  renewed  with  sweet 
highly  coloured  liquor  as  each  new  pack  is  treated. 
Regarding  the  employment  of  sulphuric  acid  for  this 
purpose,  Mr.  Schultz  observes,  "  Vitriol-raised  leather, 
when  treated  in  the  after  process  in  weak  liquors,  produces 
a  most  unsatisfactory  result.  The  grain  is  poor,  the  fibre 
coarse  and  *  hatty.'  I  do  not  here  attempt  to  solve  the 
mooted  question  whether  vitriol  does  not  destroy  the 
tannin.  It  is  conceded  that  it  will  plump  and  hold  the 
fibre  and  will  facilitate  the  tanning,  but  whether  these 
advantages  in  an  economical  point  of  view  are  not  more 
than  counterbalanced  by  its  destructive  action  on  both 

Ji 


242  LEATHER  MANUFACTURE. 

fibre  and  the  tannin  I  shall  leave  for  future  experience  to 
determine."  He,  however,  concedes  that  vitriol  "pre- 
serves the  hides,  and  holds,  when  combined  with  salt,  the 
gelatine  from  decay,"  and  he  moreover  states  that  "  all  the 
green  sheepskins  that  come  from  England  to  this  country 
(America)  in  casks  are  preserved  by  this  process,  and  may 
be  so  held  without  damage  for  years ; "  but  he  further 
observes  that  unless  the  acid  in  these  skins  is  neutralised 
before  they  are  put  into  tan  liquor,  they  swell  to  more 
than  double  their  wonted  thickness,  and  will  tear  as  easily 
as  brown  paper. 

While  Mr.  Schultz  allows  that  sulphuric  acid  raising 
may  be  adopted,  without  material  damage,  for  hides  which 
have  been  limed,  he  says,  "  In  my  judgment  vitriol  should 
never  be  used  to  raise  purely  sweat  stock,"  in  which, 
we  imagine,  none  will  differ  from  him ;  while  it  is  equally 
clear  'that  lime  would  be  an  appropriate  steep  for  sweated 
stock. 

Handling. — In  America  the  system  of  handling  by 
withdrawing  the  packs  and  allowing  them  to  drain  and 
then  returning  them  to  the  handlers,  as  is  usually  practised 
in  this  country,  or  of  working  the  handlers  in  rounds,  have 
been  substituted  by  mechanical  appliances  which  reduce 
the  labour  of  the  workmen  in  this  branch  of  the  business 
to  a  minimum.  The  most  generally  adopted  contrivances 
are  the  hand-reel  (Fig.  43)  and  the  "rocker."  The  former 
machine  is  placed  in  the  alley- way  between  the  pits  to 
be  shifted,  and  the  hides  to  be  transferred  being  tied 
together,  are  forced  over  from  one  pit  to  another  by  means 
of  the  revolving  drum,  which  is  turned  by  its  handle  by 
one  man,  while  a  second  man  adjusts  the  hides  in  the 
"  head  "  pit.  It  takes  only  four  minutes  for  two  men  to 
transfer  150  hides  from  one  pit  to  another. 

The  Rocker  Handler  is  a  frame  set  in  the  top  of  pits, 
and  is  made  of  wood.  The  frame  fills  the  pit  within  two 
inches  of  each  end  and  one  inch  on  each  side,  so  that 
when  it  rocks  from  the  centre  it  will  play  without 
touching  (Fig.  44).  It  should  be  made  of  two-inch  timber, 
and  framed  two  by  six  inches.  The  end-pieces  should  be 


AMERICAN  TANNING. 


243 


made  of  hard  wood  not  liable  to  split,  since  these  have  to 
bear  the  strain  of  the  whole  pack.  The  centre  of  this 
frame  rests  on  pivots,  supported  by  uprights  from  the 
bottom  of  the  pits.  A  stop  at  each  end  of  the  pit  prevents 
the  rocker  from  dipping  more  than  about  eight  inches. 
The  hides  are  attached  alternately  by  the  head  and  tail  to  the 
end-pieces,  with  backs  up  and  bellies  down,  by  means  of 
hard  wooden  pins  permanently  fastened  in  the  head  frame- 
pieces.  Usually  one  end  is  fastened  directly  to  or  over 
the  pin,  and  the  other  by  an  adjustable  string  which 
need  not  be  more  than  a  foot  long,  and  may  be  made  by 
a  permanent  slip  knot  to  act  continuously. 


Sometimes  "  white  spots  "  appear  upon  the  surfaces  of 
sweated  hides  after  having  been  partially  coloured  in  the 
handlers.  These  spots  have  been  proved  to  be  due  to 
grease  left  by  imperfect  beam  work,  and  the  most  approved 
remedy  for  this  is  caustic  soda,  a  solution  of  which  is 
rubbed  over  the  spots,  when  they  quickly  disappear. 
This  defect  does  not  apply,  of  course,  to  limed  goods. 

The  Layers. — Respecting  the  proper  disposition  of  the 
hides  in  these  pits,  Schultz  observes,  "  The  question  has 
often  been  raised  whether  the  hides  should  be  laid  grain 
or  flesh  side  up  in  the  layers.  The  practice  is  to  lay 
grain  up,  and  this  is  justified  on  the  ground  that  in 


244  LEATHER   MANUFACTURE. 

'  hooking  up '  tlie  grain  is  more  apt  to  be  scratched  and 
marked  than  if  laid  flesh  side  up.  If,  as  it  seems  quite 
likely,  colour  is  seriously  affected  (particularly  hemlock 
tannings),  by  the  settling  of  the  colouring  matter  on  the 
grain,  and  a  deeper,  darker  red  is  the  result,  then  I  think 
tanners  may  well  inquire  whether,  in  their  attempts  to 
avoid  hook-marks,  they  do  not  entail  upon  their  stock  a 
worse  evil.  Besides,  I  will  suggest  in  this  connection 
whether  it  is  not  probable  that  tannin  will  enter  the  fibre 
of  the  hide  more  naturally  from  the  flesh  than  from  the 
grain  surface.  The  pores  of  the  hide,  when  on  the 
animal,  certainly  do  open  their  valves  outwardly  from  the 
flesh,  for  all  the  emanations  of  the  animal  body  go 
through  these  outward- opening  valves  or  pores  of  the 
skin,  and  never  receive  back  from  the  grain  to  the  flesh." 
To  this  we  may  add,  as  a  further  suggestion,  that  while 
the  tannin  of  the  bark  and  ooze  is  being  gradually 
absorbed  by  the  hides,  the  liquor  is  kept  in  a  continual 
state  of  imperceptible  movement,  by  which  the  tendency 
of  the  exhausted  liquid  would  always  be  upward ;  while 
the  liquid  renewed  with  tannin  from  the  ground  bark, 
being  now  heavier,  would  take  its  place,  and  thus  a  con- 
tinual upward  movement  would  result,  as  in  the  circulation 
of  sap  in  a  tree,  though  not  of  course  with  the  same  vigour. 


CHAPTER  XIX. 
HEMLOCK  TANNING. 

Pratt's  System  of  Tanning. — Hemlock  Tanning  of  New   Lebanon. — 
Hibberd's  Process. 

THE  great  success  which  attended  the  employment  of 
hemlock-bark  in  some  parts  of  the  United  States  induced 
English  tanners  to  turn  their  attention  to  this  prolific 
source  of  tanning  material,  and  during  the  past  thirty 
years  or  so  an  extract  of  the  bark  has  been  imported  from 
Canada  in  large  and  increasing  quantities.  The  hemlock 
spruce-fir  abounds  in  the  northern  states  of  Pennsylvania 
and  Canada,  and  the  readiness  and  cheapness  with  which 
the  bark  is  obtained  have  rendered  it  the  chief  tanning 
material  of  those  states,  and  a  source  of  considerable  in- 
dustry in  Canada.  The  extract  comes  over  to  this  country 
in  casks,  of  the  consistence  of  treacle,  and  is  of  a  dark 
brown  colour.  This  extract  is  not  soluble  in  cold  water, 
owing  to  the  large  amount  of  resinous  matter  it  contains, 
but  it  is  freely  dissolved  in  water  at  150°  Fahr.  It  may 
be  employed  alone,  but  owing  to  the  indifferent  colour  it 
imparts  to  leather,  it  is  generally  used  in  combination 
with  other  tanning  materials.  According  to  Ramspacher, 
it  yields  25  per  cent,  of  tannin. 

Pratt's  System  of  Tanning.— The  Hon.  Zadock  Pratt, 
who  was  one  of  the  most  skilful  and  experienced  manu- 
facturers of  leather  in  the  United  States,  furnished  Dr. 
Morfit  with  some  very  elaborate  and  interesting  particulars 
concerning  his  system  of  working,  during  a  long  series 
of  years,  at  his  famous  tanneries  at  Prattsville,  N.Y., 
from  which  we  make  the  following  interesting  extracts  : — 


246  LEATHER  MANUFACTURE. 

"  Since  I  first  commenced  business,  the  gain  in  weight, 
in  converting  hides  into  leather,  has  been  increased  nearly 
50  per  cent.  That  is,  from  a  quarter  to  a  third  more 
leather  can  now  be  obtained  from  a  given  quantity  of 
hides  than  at  the  time  when  I  learnt  my  trade  at  my 
father's  tannery,  conducted  in  the  old-fashioned  way. 
The  great  improvement  in  weight  seems  to  have  been 
gained  by  the  judicious  use  of  strong  liquors  or  '  ooze/ 
obtained  "from  finety-  ground  bark,  and  by  skilful  tanning. 
The  loss  and  wastage  upon  hides,  from  hair,  flesh,  &c., 
ma}7  be  estimated  at  from  12  to  15  per  cent.  In  order  to 
produce  heavy  weights,  the  hides  should  not  be  reduced 
too  low  in  the  beam  house,  and  should  be  tanned  quickly 
with  good  strong  liquors,  particularly  in  the  latter  stage  of 
the  operation.  To  green  hides  particularly,  nothing  can 
be  more  injurious  than  to  suffer  them  to  remain  too  long 
in  weak  ooze.  They  become  too  much  reduced,  grow  soft, 
flat,  and  flabby,  lose  a  portion  of  their  gelatine,  and  refuse 
to  '  plump  up/  On  the  other  hand,  the  effects  of  an  early 
application  of  ooze  that  is  too  strong  and  too  warm  to 
green  hides  is  very  injurious.  It  contracts  the  surface 
and  fibres  of  the  skin,  tanning  at  once  the  exterior  layers 
so  '  dead/  as  it  is  termed,  as  to  shut  up  the  pores  and 
prevent  the  tannin  from  penetrating  the  interior.  This 
renders  the  leather  harsh  and  brittle.  It  will  be  seen 
from  this  that,  in  the  question  of  the  proper  strength  of 
liquor  alone,  there  is  room  for  the  exercise  of  the  greatest 
judgment  and  the  most  extensive  experience.  In  the 
impossibility  of  adapting  fixed  rules  to  the  innumerable 
variety  of  cases,  nothing  can  be  depended  upon  but  the 
judgment  of  the  practical  tanner. 

"  In  softening  hides  and  preparing  them  for  the  process 
of  tanning,  a  great  deal  depends  upon  the  judgment  of 
the  person  superintending  the  operation,  inasmuch  as  the 
diversities  in  the  qualities  and  characteristics  of  the  hides 
render  it  impossible  to  subject  them  to  any  more  than  a 
general  mode  of  treatment.  In  *  sweating/  the  character 
of  the  hides  and  the  temperature  are  essential  but  ever- 
varying  considerations.  As  a  general  rule,  however,  the 


HEMLOCK  TANNING.  247 

milder  the  process  of  preparing  the  hides  for  the  bark 
the  better.  Unnecessarily  severe  or  prolonged  treatment 
is  inevitably  attended  with  loss  of  gelatine,  and  a  conse- 
quent loss  of  weight  and  strength  in  the  leather.  Too 
high  a  temperature  is  particularly  to  be  avoided.  In 
almost  every  lot  of  hides,  particularly  Orinocos,  however, 
there  are  generally  some  that  prove  very  intractable, 
resisting  all  the  ordinary  modes  of  softening.  For  such, 
a  solution  of  ashes,  potash,  or  even  common  salt,  will  be 
found  to  be  beneficial,  and  peculiarly  so  in  hot  weather. 
As  I  have  said,  no  precise  rule  can  be  given  as  to  the 
length  of  time  required  for  the  preliminary  processes  of 
soaking  and  '  sweating/  so  much  depending  upon  the 
qualities  of  the  hides  and  the  temperature  at  which  these 
operations  are  conducted. 

"  The  following  table  may,  however,  be  found  useful  in 
conveying  an  approximation  to  a  definite  idea  of  the 
practice  in  my  tannery : — 

Soaking — 

Temperature:    40°  60°  60°  7<F 

Days.  Days.  Days.  Days. 

Buenos  Ayres  hides 10  to  12  8  to  12  6  to    8  3  to  6 

Carthagena  and  Laguaira  . .  8  „  12  7  „    9  5  „     7  2  „  3 

Sweating — 

Buenos  Ayres  hides 15  „  20       12  „  16        8  „  12      2  „  3 

Carthagena  and  Laguaira  . .  15  „  20       10  ,,15         6  „    8       2  „  3 

"  I  would  here  remark  that  I  changed  the  process  of 
liming  to  sweating  in  1836 — the  only  change  in  tanning 
I  have  made  in  twenty  years ;  and  for  heavy  sole  leather 
it  has  been  proved  to  be  quite  as  good  as  liming,  if  not 
better,  and  somewhat  cheaper,  besides  yielding  a  greater 
gain  in  weight,  and,  when  well  tanned,  making  leather 
more  impervious  to  water.  Liming  and  bating,  however, 
for  upper  and  light  leather,  is  preferable,  and  if  the  same 
improvements  had  been  adopted  with  the  lime  process  of 
strong  liquid  and  quick  tanning,  it  is  not  yet  certain 
that  the  same  results  would  not  have  been  attained. 

"  Salted  hides  do  not  require  more  than  two-thirds  the 
time  to  soak,  but  generally  longer  to  sweat.  After  the 


24$  LEATHER  MANUFACTURE. 

hides  are  prepared  for  tanning,  the  next  process  is  what 
is  commonly  called  *  handling/  which  should  be  performed 
two  or  three  times  a  day,  in  a  weak  ooze,  until  the  grain 
is  coloured.  New  liquors,  or  a  mixture  of  new  and  old, 
are  preferable  for  Spanish  or  dry  hides,  old  liquors  for 
slaughters.  They  are  then,  after  a  fortnight,  laid  away 
in  bark,  and  changed  once  in  two  or  four  weeks,  until 
tanned.  Much  care  and  judgment  are  necessary  in  pro- 
portioning the  continually  increasing  strength  of  the 
liquors  to  the  requirements  of  the  leather  in  the  different 
stages  of  the  process.  The  liquors  should  also  be  kept  as 
cool  as  possible,  within  certain  limits,  but  ought  never  to 
exceed  a  temperature  of  80°  ;  in  fact,  a  much  lower  tem- 
perature is  the  maximum  point  if  the  liquor  is  very 
strong,  too  high  a  heat,  with  a  liquor  too  strongly  charged 
with  the  tanning  principle,  being  invariably  injurious  to 
the  life  and  colour  of  the  leather.  From  this  it  would 
seem  that  time  is  an  essential  element  in  the  process  of 
tanning,  and  that  we  cannot  make  up  for  the  want  of  it 
by  increasing  the  strength  of  liquor  or  raising  the  tem- 
perature at  which  the  process  is  conducted,  any  more  than 
we  can  fatten  an  ox  or  a  horse  by  giving  him  more  than 
he  can  eat. 

"I  have  mentioned  the  injurious  effects  resulting  from 
too  strong  a  solution  of  the  active  principle  of  the  bark  ; 
on  the  other  hand,  the  use  of  too  weak  solutions  is  to  be 
avoided.  Hides  that  are  treated  with  liquor  below  the 
proper  strength  become  relaxed  in  their  texture,  and  lose 
a  portion  of  their  gelatine ;  the  leather  necessarily  loses 
in  weight  and  compactness,  and  is  much  more  porous  and 
pervious  to  water.  The  warmer  these  weak  solutions  are 
applied  the  greater  is  the  loss  of  gelatine.  To  ascertain 
whether  a  portion  of  weak  liquor  contains  any  gelatine  in 
solution,  it  is  only  necessary  to  strain  a  little  of  it  into  a 
glass,  and  then  add  a  small  quantity  of  a  stronger  liquor. 
The  excess  of  tannin  in  the  strong,  seizing  upon  the  dis- 
solved gelatine  in  the  weak  liquor,  will  combine  with  it  and 
be  precipitated  in  flakes  of  a  dark  curdled  appearance  to  the 
bottom.  At  the  Prattsville  tannery  the  greatest  strength 


HEMLOCK  TANNING.  249 

of  liquor  used  for  handling,  as  indicated  by  Pike's  barko- 
ineter,  is  16° ;  of  that  employed  for  laying  away,  the 
greatest  strength  varies  from  30°  to  45°. 

"After  the  leather  has  been  thoroughly  tanned  and 
rinsed  or  scrubbed  by  a  brush,  machine,  or  broom,  it  will 
tend  very  much  to  improve  its  colour  and  pliability  to 
stack  it  up  in  piles  and  allow  it  to  sweat  until  it  becomes 
a  little  slippery  from  a  kind  of  mucus  that  collects  upon 
its  surface.  A  little  oil  added  at  this  stage  of  the  process, 
or  just  before  rolling,  is  found  to  be  very  useful.  Great 
caution  is  necessary  in  the  admission  of  air  in  drying  when 
first  hung  up  to  dry.  No  more  air  than  is  sufficient  to 
keep  the  sides  from  moulding  should  be  allowed.  Too 
much  air — or,  in  other  words,  if  dried  too  rapidly  in  a 
current  of  air — will  injure  the  colour,  giving  a  darker  hue, 
and  rendering  the  leather  harsh  and  brittle.  To  insure 
that  the  thick  parts,  or  butts,  shall  roll  smooth  and  even 
with  the  rest  of  the  piece,  it  is  necessary  that  the  leather 
should  be  partially  dried  before  wetting  down  for  rolling, 
and  that  when  wet  down  it  should  lay  long  enough  for 
every  side  to  become  equally  damp  throughout." 

The  average  time  for  tanning  by  hemlock,  in  America, 
amounts  to  five  months  twenty-seven  days  ;  sole  leather, 
however,  occupies  from  four  to  six  months,  according  to 
the  strength  of  the  liquor  used  and  number  of  sides  in  the 
vats,  and,  according  to  Pratt,  the  quicker  the  tanning  is 
effected  the  better  is  the  result. 

Hemlock  Tanning  of  New  Lebanon,  N.  J.  —  Dussaucc 
gives  the  following  description  of  the  process  of  tanning 
with  hemlock  at  the  Shaker  tannery  of  New  Lebanon,  as 
furnished  to  him  by  the  Shaker  tanner,  Mr.  Fred.  Sizer. 
"  I  take  a  pack  of  calf  skins — say  100  dry  skins — and  put 
them  in  a  water  vat  to  soak  ;  after  they  have  soaked  two 
or  three  days  I  take  them  out  and  mill  them  (a  wheel  is 
best  for  milling  hides) ;  I  then  beam  them  on  the  flesh 
side,  removing  all  the  lean  meat  and  grease  from  the 
skins,  stretching  them  out  well  with  the  beaming- knife, 
and  put  these  into  a  vat  of  clean  water  until  they  are  soft 
enough  to  go  into  the  lime.  They  must  be  as  soft  as 


250  LEATHER  MANUFACTURE. 

when  they  came  from  the  animal,  or  as  near  that  as  you. 
can  get  them.  If  the  hides  are  not  soft  before  going  into 
the  lime,  they  never  can  be,  and  the  leather  will  always 
be  hard. 

' 'Fresh  hides,  that  come  direct  from  the  butchers,  are 
put  in  water  a  day  or  two  ;  change  the  water  once,  beam 
them  on  the  flesh  side ;  they  are  then  ready  for  the  lime. 
I  make  my  lime  in  a  vat  8  feet  long  by  4  wide  and  4  deep. 
One  bushel  of  lime  and  2  gallons  of  soft  soap  put  in  the  vat 
two-thirds  full  of  water  will  make  a  lime  sufficient  for 
100  calf  skins  or  five  sides  of  upper  leather.  The  hides 
should  be  handled  out  every  other  day,  while  in  the  lime, 
to  air  and  change  their  position  ;  then  stir  the  lime  well 
before  they  are  put  back.  The  lime  needs  strengthening 
every  time  a  new  pack  is  put  in  by  adding,  say  half-a- 
bushel  of  lime  and  two  or  three  quarts  of  soap.  I  lime 
my  calf  skins  and  upper  leather  hides  until  the  hair  comes 
off  easily,  but  sole  leather  hides  should  be  limed  as  little 
as  possible  to  get  the  hair  off ;  then  unhair  them,  wash 
them  out  in  the  mill,  beam  them  on  the  flesh  side,  trim 
off"  the  pates  and  shanks,  and  put  them  in  the  bate. 

"  I  put  five  or  six  bushels  of  hens'  dung  into  a  vat  of  the 
same  dimensions  as  used  for  the  lime  and  fill  two-thirds  full 
of  water  and  let  it  stand  two  or  three  days  to  ferment.  I  let 
my  skins  remain  in  the  bate  two  or  three  days  in  warm 
weather  and  longer  in  cold  ;  haul  them  two  or  three  times 
while  in  the  bate,  and  work  them  twice  on  the  grain  with 
a  common  worker  on  the  tanner's  beam  ;  mill  them  .before 
working  the  last  time,  then  beam  them,  and  they  are 
ready  for  the  tan-vats.  I  make  a  liquor  of  moderate 
strength  to  handle  them  in,  put  them  in  this  liquor,  and 
stir  them  with  a  pole  a  while,  then  handle  them  up  smooth 
on  a  box  or  rack  three  or  four  times  in  the  course  of  the 
day ;  let  them  remain  in  this  until  the  next  morning,  then 
change  the  liquor,  giving  them  about  the  same  strength 
as  at  first ;  handle  them  two  or  three  times  a  day  in  the 
liquor,  and  when  this  is  exhausted  change  again,  and 
handle  less  as  the  skins  get  coloured  and  the  grain  set. 

"  I  make  my  liquors  of  hemlock-bark,  ground  and  put 


HEMLOCK  TANNING.  251 

in  leaches,  and  pump  in  the  exhausted  liquor.  The  first 
strength  of  my  leaches  I  draw  off  the  sole  leather  vats.  I 
draw  off  the  leaches  two  or  three  times  before  taking  it 
from  my  upper  leather  and  calf  skins,  and  these  I  keep  in 
mild,  sweet  liquors  through  the  whole  tanning  process.  I 
handle  my  hides  and  calf  skins  through  until  tanned, 
changing  the  liquors  as  they  get  exhausted.  After  they 
get  well  along  I  handle  them  three  times  a  week.  They 
will  do  to  lay  longer,  but  will  tan  faster  if  handled  often. 
When  my  calf  skins  have  been  in  the  tan  two  or  three 
weeks  I  shave  down  the  necks,  and  after  my  upper 
leather  has  been  in  four  or  five  weeks  I  shave  it  down  to 
a  proper  thickness. 

"  In  my  experience  in  tanning,  which  has  extended 
through  forty- two  years,  I  have  used  both  hemlock  and 
oak  bark,  and  I  find  that  mild  sweet  liquors  are  far  best 
for  tanning  all  kinds  of  upper  leather.  The  hide  in  the 
raw  state  is  tougher  than  when  tanned,  and  that  toughness 
ought  to  be  preserved  as  much  as  possible,  to  make  good 
pliable  leather,  and  the  slow  process  of  tanning  with  mild 
liquors  will  do  it.  Strong  liquors  have  a  tendency  to 
make  the  leather  hard  and  liable  to  crack.  The  hides  for 
upper  leather  should  not  be  tanned  any  more  than 
thoroughly  through ;  if  tanned  longer  than  this  it  has 
the  same  effect  upon  them  as  strong  liquor  ;  but  the 
longer  sole  leather  is  tanned  the  better.  When  I  think 
my  leather  is  nearly  struck  through  I  try  it  by  cutting 
into  the  thickest  edge,  and  when  tanned  through  take  it 
up  and  scour  it  out  on  the  wheel  to  cleanse  it  from  the  tan 
and  soften  the  grain  ;  then  take  them  to  the  currying 
shop,  and  the  calf  skins  I  skive,  and  uppers  smooth  down 
with  the  currying  knife ;  then  put  them  in  a  tub  of  water 
and  scour  them  on  the  table  with  a  brush,  stone,  and 
slicker ;  dry  them  a  little,  temper  them,  and  then  put 
them  on  the  table  and  set  them  on  the  grain  side  to  work 
the  grain  out  smooth.  After  that  apply  some  thin  stuff- 
ing made  of  oil  and  tallow,  then  turn  them  over,  flesh  side 
up,  and  set  them  out  with  an  iron  slicker ;  then  apply  the 
stufiiiig  more  plentifully,  made  thicker  with  more  tallow ; 


252  LEATHER  MANUFACTURE. 

then  hang  them  on  sticks  and  dry  them,  and  then  pack 
them  down  in  a  pile,  and  let  them  stay  two  weeks.  I 
then  take  them  and  rub  off  what  stuffing  does  not  strike 
in,  and  whiten  them  with  a  currying  knife  or  slicker. 
I  commonly  whiten  my  calf  skin  and  kips  with  a  slicker, 
and  finish  in  the  French  style.  Since  the  French  de*gras 
has  come  into  use,  I  have  used  it  for  calf  skins  and  kips. 
I  have  also  for  some  time  used  tansy  in  my  liquors. 
There  is  an  acid  in  tan  that  injures  the  leather  which 
tansy  neutralises  and  keeps  the  liquor  sweet." 
Hibberd's  Process. — This  process  consists — 
First,  in  the  use  of  a  compound  of  lime,  wood  ashes, 
or  potash,  and  salt  for  removing  the  hair  or  wool,  and 
also  for  the  purpose  of  so-called  "liming,"  instead  of 
using  the  lime  alone.  Lime  and  ashes  have  been  used 
separately  for  the  purpose  of  removing  the  hair,  wool, 
&c.,  but  lime  alone  requires  several  days,  and  in  cold 
weather  weeks,  to  effect  these  objects,  by  which,  the 
inventor  says,  the  skin  is  more  or  less  injured.  "  On 
the  other  hand,  ashes  alone  act  too  rapidly,  and  would 
destroy  the  skins  altogether.  When  lime,  ashes,  and 
salt  are  combined  in  proper  proportions,  the  salt  modifies 
the  action  of  the  alkalies,  and  protects  the  skin  from 
their  caustic  properties,  so  that  the  process  of  unhairing 
and  liming  are  both  rendered  more  expeditious  and  safe 
than  by  the  old  method,  while  the  texture  of  the  skin  is 
uninjured,  and  consequently  the  leather  is  much  stronger." 
Second,  in  the  use  of  a  composition  of  salt,  sulphuric 
acid  and  sumac,  oak,  hemlock-bark,  or  other  tanning 
material  for  the  process  of  tanning.  The  salt,  sulphuric 
acid  and  tannin  being  mixed  together  in  water  in  certain 
proportions  hereafter  mentioned,  a  portion  of  the  salt  is 
decomposed  by  the  acid,  forming  sulphate  of  soda,  and 
setting  free  muriatic  acid,  which  acid,  being  absorbed  by 
the  water,  acts  directly  and  rapidly  on  the  skins,  opening 
their  pores,  and  preparing  them  for  the  tannin,  which, 
being  present  also  in  the  mixture,  immediately  and  readily 
unites  with  the  gelatine  of  the  skin,  forming  leather  more 
expeditiously  and  perfectly  than  by  the  usual  methods. 


HEMLOCK  TANNING.  253 

Preparation  of  the  Skins. — By  this  process  the  skins 
may  be  prepared  as  usual,  but  the  inventor  prefers  to 
employ  the  following,  which  he  calls  composition  No.  I : — 

Quicklime,  fresh  slaked i  bushel. 

Wood  ashes   |       ,, 

Common  salt 3  pints. 

For  the  ashes  may  be  substituted  from  3  Ibs.  to  5  lb?. 
of  potash. 

To  remove  the  hair  or  wool,  the  above  composition  is  to 
be  mixed  with  sufficient  water  to  make  a  thick  paste,  and 
applied  to  the  flesh  side  of  the  hides  in  the  usual  way,  the 
skins  to  be  folded  and  kept  at  a  temperature  of  summer- 
heat.  In  a  few  hours  they  will  be  ready  to  pull.  For 
"liming"  or  " ashing,"  he  uses  the  same  composition, 
No.  1,  mixed  with  a  sufficient  quantity  of  water  in  a  vat 
to  immerse  the  number  of  skins  required  to  be  treated. 
One  bushel  of  the  mixture  is  equivalent  to  one  bushel  of 
lime  alone.  The  liming  and  ashing  process  may  be  con- 
ducted at  a  temperature  of  40°  to  60°  Fahr. 

Composition  for  Tanning. — For  six  dozen  full-sized  sheep, 
deer,  goat,  or  similar  skins  of  the  same  size  : — 

Common  salt 18  Ibs. 

Sulphuric  acid 2  „ 

Sicily  sumac,  or  quercitron  bark  36  „ 

Muriatic  acid    2  ounces. 

Dried  clover , . . . .     18  Ibs. 

Soft  water 150  gallons. 

The  sumac  or  dyestuffs  are  first  exhausted  with  water, 
and  then  the  salt  is  added  to  the  liquor,  apportioned  so  as 
to  ensure  perfect  solution.  The  acids  are  afterwards  added, 
and  the  mixture  thoroughly  incorporated  by  stirring. 


CHAPTER  XX. 
TANNING  BY  ELECTRICITY. 

Ward's    Process.  —  Gaulard's    Process.  —  Gaulard's    Second   Process.— 
Meriten's  Process. — Crosse's  Process. 

Tanning  by  Electricity.— Considering  the  many  pur- 
poses to  which  the  electric  current  has  been  applied,  and 
the  growing  belief  that  this  remarkable  force  is  yet  sus- 
ceptible of  many  applications  in  the  arts,  it  is  not  to  be 
wondered  at  that  endeavours  should  be  made  to  utilise 
the  current  in  the  process  of  tanning.  Whether  success 
will  attend  the  employment  of  electricity  in  the  tannery 
has  yet  to  be  determined,  and  this,  of  course,  can  only  be 
done  by  careful  and  unprejudiced  trial.  The  time  has  come, 
we  hope,  when  manufacturers  cease  to  ignore  new  modes 
of  procedure  merely  on  the  ground  that  they  are  novel. 

Ward's  Process. — The  inventor  states  that  the  object 
of  his  invention  is  "  the  tanning  of  hides  and  skins  by  a 
more  speedy  and  efficient  process  than  heretofore,  in  suit- 
ably arranged  vats  or  tanks,  by  the  aid  of  electricity," 
and  it  is  effected  in  the  following  manner :  he  employs 
the  ordinary  vats  or  tanks,  which  are  lined  with  india- 
rubber  cloth,  or  other  non-conducting  substance.  The 
vats  are  filled  with  tan  liquor,  and  the  hides  suspended 
therein.  The  electric  current  is  obtained  by  means  of  a 
suitable  battery.  The  effect  of  this,  he  states,  is  that  the 
current  passes  through  the  whole  contents  of  the  vats, 
and  the  tanning  process  instantly  commences,  and  con- 
tinues until  the  strength  of  the  liquor  is  absorbed,  when, 
if  desired,  fresh  liquor  may  be  added,  and  the  current 
again  applied.  By  this  means,  the  inventor  states,  hides 


TANNING  BY  ELECTRICITY.  255 

and  skins  "may  be  fully  and  effectually  tanned  in  the 
space  of  a  few  hours." 

Gaulard's  Process. — The  inventor  says,  "  Various  ob- 
servations on  the  tanning  of  skins  having  demonstrated 
that  the  reaction  produced  has  been  the  decomposition  of 
the  watery  juice  by  the  tannin,  which  seizes  the  oxygen, 
whilst  the  hydrogen  acts  on  the  nitrogenous  matter  and 
destroys  it  in  changing  it  into  ammoniacal  salts,  I  have 
concluded  that  for  causing  a  rapid  tanning  it  suffices  to 


V_  ^- 

Fig.  45. 

oxidise  the  tannin  and  destroy  the  nitrogenous  matter  by 
causing  to  intervene  an  electric  current  into  the  juice, 
which  decomposes  the  water  of  the  liquor  into  oxygen  and 
hydrogen,  and  determines  at  the  same  time  with  rapidity 
the  reaction  above  mentioned." 

In  carrying  out  the  process  the  hides  or  skins  are  dis- 
posed as  shown  in  the  accompanying  drawing.  Fig.  45 
is  a  tub  A  ;  on  the  upper  floor  B  of  the  double  bottom  B  B1, 
the  hides  are  stratified  in  the  usual  way,  that  is  to  say, 
with  alternate  layers  of  the  hides  or  skins  and  tannin.  In 
the  space  between  the  two  floors  of  the  double  bottom  B  B1 


256 


LEATHER  MANUFACTURE. 


are  placed  two  parallel  charcoal  blocks  0  0,  fixed  by  the 
aid  of  copper  clamps  D  D.  The  two  charcoal  blocks  o  0 
are  put  into  communication  by  means  of  the  wires  a  and  b 
with  the  two  poles  of  any  electric  generator,  whereupon 
the  decomposition  of  the  watery  juice  into  its  two  elements, 
oxygen  and  hydrogen,  takes  place,  and  the  rapid  assimila- 
tion of  the  tannin  and  the  hides  or  skins  is  effected. 

Gaulard's  Second  Process. — Eeferring  to  the  former 
patent  by  the  same  inventor,  the  patentee  says,  "  Instead 
of  placing  both  poles  [of  the  electric  generator]  in  the 


Fig.  46. 

middle  of  the  vessel,  and  thus  causing  the  two  gases 
evolved  by  the  decomposition  of  the  water  [oxygen  and 
hydrogen]  to  act  simultaneously,  one  only  of  the  elec- 
trodes is  placed  in  the  centre  of  the  vessel,  the  other 
being  arranged  in  a  parallel  plane,  but  in  a  corner,  and  in 
the  centre  of  a  passage  or  conduit,  arranged  as  illustrated 
(see  Fig.  46)  in  the  drawing,  that  is  to  say,  extending  to 
about  four  inches  from  the  bottom  of  the  vessel.  The  vessel 
is  filled  with  weak  liquor,  and  the  hides  are  suspended 
therein  from  wooden  crossbars  resting  on  the  sides  of  the 
vessel.  The  electric  current  is  then  caused  to  pass  in  such 
a  manner  that  the  negative  pole  is  in  the  centre  of  the 
vessel  and  the  positive  pole  is  in  the  '  conduit/  Under 


TANNING  BY  ELECTRICITY. 


257 


these  conditions  the  hydrogen  alone  acts  upon  the  leather, 
and  causes  the  rapid  destruction  of  the  nitrogenous 
matter  contained  therein.  After  undergoing  this  treat- 
ment for  eight  days,  the  liquor  is  changed  for  a  stronger 
tanning  solution.  The  current  is  then  reversed,  so  that 
the  pole  in  the  middle  of  the  vessel  becomes  the  positive 
pole  and  the  pole  in  the  conduit  the  negative.  The 
oxygen  alone  then  acts  upon  the  liquid,  inducing  a  rapid 
oxidation  of  the  tannin,  and  its  precipitation  in  this  con- 
dition in  the  cells  formed  by  the  gelatine  and  fibrine  of 

i  ; 


JL 


Fig.  47. 

the  hide.  The  hydrogen  escapes  into  the  air  through  the 
conduit.  Under  these  conditions  the  tannin  is  effected  in 
about  fifteen  days,  and,  in  order  to  make  the  leather  more 
weighty,  a  stronger  liquor  must  be  employed,  or  the  hides 
may  be  stratified  with  layers  of  tan,  as  in  the  ordinary 
method,  at  the  same  time  keeping  up  the  electrical  action. 
A  wooden  grating,  arranged  at  a  height  of  about  eight 
inches  from  the  bottom  of  the  vessel,  is  employed  to  keep 
the  electrodes  from  direct  contact  with  the  leather,  as 
shown  in  the  engraving,  Fig.  47." 

Meriten's   Process. — The   bottom    of   the    tan-pit   is 
composed  of  a  block  or  slab  of  conducting  carbon  or  char- 

s 


258  LEATHER  MANUFACTURE. 

coal,  or  of  two  or  more  such  blocks  or  slabs,  covered  with 
a  layer  of  the  same  substance  in  a  coarse  powder.  A 
copper  wire  coated  with  gutta-percha  or  other  insulating 
material  is  employed,  one  end  of  which  is  connected  to  the 
carbon,  and  the  other  end,  being  carried  up  the  side  of 
the  pit  to  the  exterior,  is  connected  to  the  positive  pole 
of  a  battery.  Upon  the  bottom  so  constructed,  there  is 
placed  a  layer  of  bark  or  other  tanning  material,  suf- 
ficiently impregnated  with  water,  and  above  this  a  hide  or 
skin,  then  another  layer  of  bark  or  other  tanning  material, 
then  another  hide,  and  so  on  in  alternate  succession  to 
any  required  number.  A  sheet  or  plate  of  zinc,  in  con- 
nection with  the  negative  pole  of  the  battery,  is  disposed 
at  the  upper  part  of  the  pit,  and  rests  upon  a  layer  of  the 
tanning  material,  and  above  the  zinc  there  is  placed  a 
final  layer  of  tanning  material  sufficiently  impregnated 
with  liquid  as  before.  "  On  establishing  an  electric  cur- 
rent, a  motion  takes  place  between  the  two  poles  through 
the  hides  or  skins,  the  basic  elements  proceeding  to  the 
negative  pole  and  the  acid  elements  to  the  positive  pole, 
whereby  a  molecular  motion  is  produced  and  maintained 
throughout  the  hides  or  skins,  and  the  fixing  of  tannin  in 
their  pores  is  effected.  It  is  preferred  to  divide  each  of 
the  poles  into  two  or  more  surfaces,  according  to  the 
depth  of  the  pits  and  the  quantity  of  hides  which  they 
contain ;  but  it  is  in  all  cases  essential  that  the  anode 
(positive  pole]  should  be  composed  of  an  insoluble  ma- 
terial." This  of  course  means  carbon,  or  some  metal  not 
acted  upon  by  the  tanning  liquor  when  decomposed  by 
the  current. 

Crosse's  Process. — This  process  has  for  its  object  First, 
the  unhairing  of  hides  and  skins,  by  the  employment  of 
sulphide  of  lime,  in  which  the  hides  are  soaked,  when  the 
hair  becomes  loosened  and  may  be  removed  in  the  usual 
way.  Second,  in  producing  electric  effects  on  the  matters 
in  the  tan-pit.  On  one  side  of  the  pit  is  placed  a  plate 
of  lead,  and  on  the  other  a  plate  of  zinc,  the  plates  cover- 
ing the  sides  of  the  pit.  The  two  plates  are  connected  at 
the  upper  parts  above  the  liquid  by  a  band  of  either 


TANNING  BY  ELECTRICITY.  259 

metal.  The  skins  are  suspended  in  the  pit,  filled  with 
water,  and  remain  three  or  four  days.  The  water  is  then 
removed  or  converted  into  ooze  or  tanning  liquor,  by 
adding  bark  or  other  suitable  matter,  or  the  water  is 
replaced  by  tanning  liquor  of  a  strength  equal  to  about 
15°  of  a  saccharometer,  and  the  liquor  is  kept  up  at  that 
strength  for  a  week.  The  strength  may  be  then  increased 
to  5°  a  week  till  it  reaches  45°.  The  process  may  be 
varied,  and  the  strength  and  progressive  increase  of 
strength  in  the  tanning  liquor  modified. 


CHAPTER  XXI. 
CHEMICAL  TANNING. 

Knapp's  Processes. — Heinzerling-'s  Chrome  Process. — Heinzerling's 
Second  Chrome  Process. — Vanderstraaten's  Process. 

WE  have  been  tempted  to  adopt  the  above  heading  to  dis- 
tinguish the  processes  about  to  be  described  from  the  ordi- 
nary processes  of  tanning,  to  which  they  may  be  said  to 
have  no  resemblance.  Whether  the  manufacture  of  leather 
by  other  agents  than  tannin  will  ever  become  really  suc- 
cessful is  a  question  which  time  alone  can  decide.*  We 
know  that  alum  and  salt,  as  employed  in  the  process  of 
tawing,  produce  a  certain  effect  upon  the  skins  of  smaller 
animals — as  the  calf,  sheep,  goat,  &c. — which  renders 
them  suitable  for  certain  purposes  to  which  leather,  properly 
so  called,  would  be  wholly  unfit ;  but  whether  a  substitute 
for  tannic  acid  in  the  manufacture  of  leather  from  heavy 
hides  will  ever  be  discovered,  is  a  matter  upon  which  few 
will  venture  to  prophesy  "  onless  they  know/'  as  Artemus 
Ward  put  it.  Many  attempts  have  been  made  in  this 
direction,  and  we  may  hazard  the  prediction  that  even  if 
a  better  article  could  be  produced  without  the  agency  of 
tannin,  it  would  take  a  very  long  time  before  the  world 
— so  long  accustomed  to  the  smell  of  tan — would  believe 
in  it. 

From  the  numerous  processes  which  have  been  patented, 
we  select  several  which  have  to  some  extent  commanded 
attention,  and  at  least  one  of  which  has  been  worked  upon 
a  practical  scale:  we  allude  to  what  is  known  as  the 
chrome-tanned  leather  process  of  Dr.  Heinzerling,  carried 
out  by  the  Eglinton  Chemical  Company,  of  Glasgow. 

*  The  chrome  process  is  now  an  acknowledged  commercial  success  for 
most  of  the  lighter  kinds  of  upper  leather,  and  is  also  used  to  some 
extent  for  harness  and  belting  leather. — ED.  Fifth  Edition. 


CHEMICAL    TANNING.  261 

Knapp's  Processes. — I.  By  this  process,  which  was 
patented  in  1877,  an  oxide  salt  of  iron  is  prepared  in  the 
following  manner :  To  a  boiling  solution  of  green  vitriol 
(sulphate  of  iron)  as  much  nitric  acid  is  added  as  will 
thoroughly  oxidise  the  same.  The  effervescence  which 
takes  place  being  over,  the  operation  is  reversed,  green 
vitriol  being  added  to  the  solution  now  containing  the 
iron  oxide ;  the  second  ebullition  or  effervescence  caused 
by  this  operation  having  subsided,  the  compound  has  now 
a  syrupy  consistence,  and  is  of  a  yellow-red  colour.  If  it 
bo  slowly  evaporated,  there  remains  the  dry  iron  oxide 
salt  as  an  orange-red  transparent  varnish.  Basic  sulphate 
of  iron  manufactured  in  this  way  is  very  different  in  its 
physical  properties  from  that  of  commerce  and  described 
in  chemical  books.  This  latter  does  not  give  a  syrupy 
solution,  and  is  of  a  much  darker  colour — a  brown-yellow 
— and  decomposes  on  being  boiled  in  an  aqueous  solution. 
On  the  other  hand,  the  preparation  above  described  may 
be  boiled  in  a  solution  of  30°  to  40°  Baurne  without  decom- 
posing, and  is  in  reality  copiously  taken  up  by  the  skins 
of  animals. 

II.  To  carry  out  this  process,  the  hides  are  treated  with 
the  above  iron  salt  in  the  following  way  : — 

First  Dressing. — To  prepare  the  hides,  they  are  placed 
in  a  cold  solution  of  the  iron  oxide  salt,  and  the  dressing 
is  thus  completed  in  two,  or  at  the  most  four,  days,  accord- 
ing to  the  quantity  of  skins  or  hides  treated  at  once. 
Relaying  the  skins,  handling,  and  other  like  operations 
are  dispensed  with. 

Currying. — After  the  skins  have  been  tanned  (!)  with 
the  iron  salt  solution,  they  are  treated  with  fats  and 
greases  in  a  liquid  state,  and  with  a  new  "  iron  soap  " 
described  further  on.  The  greases  are  dissolved  in  the 
manner  now  in  use,  and  the  leather  soaked  with  them,  or 
"  stuffed,"  after  the  skins  have  been  sufficiently  dried.  In 
this  manner  the  present  expensive  and  tedious  hand  mani- 
pulation, which  makes  the  value  of  leather  so  dependent  on 
the  skill  and  attention  of  the  workmen,  is  quite  done  away 
with ;  that  is  to  say,  the  greasing  of  the  leather  by  hand 


262  LEATHER  MANUFACTURE. 

with  greases,  fat,  and  like  substances,  the  hanging  up  in 
the  drying-room,  the  tramping  in  the  drum,  and  the 
working  off  of  the  superabundant  greases,  is  thus  done 
away  with.  Besides  the  greases  now  in  use,  the  inventor 
employs  stearine  and  paraffin,  which  are  chemically  dis- 
solved in  the  usual  way.  By  the  use  of  fats  in  combina- 
tion with  the  iron  solution,  the  substances  used  for  greasing 
the  leather  are  united  in  such  a  way  on  the  fibres  of  the 
skin  as  to  form  an  "  iron  soap,"  which  is  an  entirely  new 
product. 

The  iron  soap  is  produced  by  precipitating  soap  from  its 
solution  by  means  of  the  afore-mentioned  iron  salt  solu- 
tion. The  iron  soap,  combined  or  not  with  fatty  emulsions, 
is  worked  into  the  leather  by  means  of  a  drum.  This 
drum  consists  of  a  tramping  drum,  which  revolves  round 
a  hollow  axle,  this  latter  being  connected  with  a  blower 
by  a  pipe.  The  blower  drives  the  air  through  the  hollow 
axle,  and  through  pipes  to  the  circumference  of  the 
tramping  drum,  and  through  the  hides. 

III.  In  this  process  a  solution  of  sulphate  of  peroxide 
of  iron  is  produced,  which  acts  in  the  same  manner  as  the 
solution  before  described,  but  with  better  effect  in  tanning. 
Moreover,  it  is  chemically  a  different  compound.      This 
solution  is  produced  by  adding  equivalent  quantities  of 
sulphuric  acid  and  nitrate  of  soda,  instead  of  nitric  acid,  to 
the  boiling  solution  of  the  sulphate  of  iron.     With  the 
exception  of  these  substitutions,  this  solution   is   to   be 
treated  in  the  same  way  as  before.     The  solution  differs 
from  the  former  chiefly  by  the  soda  of  the  nitrate  of  soda 
entering  into  the  new  compound  as  a  constituent  part, 
along  with  the  peroxide  of  iron  and  the  sulphuric  acid. 

IV.  In  this  process  the  inventor  treats  the  leather  with 
albuminous  matters,  as  blood,  &c.,  in  such  a  way  that  they 
form  a  precipitate  and  compound  with  the  peroxide  of  iron 
of  the  "tanning"  salt  before  described. 

Heinzerling's  Chrome  Process. — The  hides  are  un- 
h  aired  and  soaked  in  the  usual  way,  after  which  they  are 
placed  in  a  solution  of  from  1  to  5  per  cent,  of  acid  or 
neutral  chromate  of  potash,  chromate  of  soda,  or  chromate 


CHEMICAL   TANNING.  263 

of  magnesia,  and  from  1  to  10  per  cent,  of  alum,  or  a 
corresponding  quantity  of  sulphate  of  alumina.  To  these 
may  be  added  from  1  to  10  per  cent,  of  chloride  of  sodium 
(common  salt).  In  this  bath  the  skins  are  left  a  longer  or 
shorter  time,  according  to  their  texture  and  thickness. 
After  the  hides  have  been  in  the  solution  for  some  days,  a 
small  percentage  of  yellow  or  red  prussiate  of  potash  is 
added,  or  may  be  introduced  at  the  commencement  of  the 
operation.  The  prussiate  of  potash  is  preferably  used  for 
leather  which  is  afterwards  to  be  blackened,  and  may  be 
dispensed  with  for  other  leather.  In  order  to  fix  the 
tanning  (!)  stuffs  in  the  leather,  manipulated  as  above 
described,  the  hides  should  be  placed  for  a  short  time  in  a 
solution  consisting  of  1  or  2  per  cent,  of  chloride  of  barium, 
1  or  2  per  cent,  of  acetate  of  lead,  or  the  same  proportion 
of  soap.  The  hides  can  be  dried  in  the  usual  manner. 

The  smooth,  damp  hides  are  next  dipped  for  a  short 
time  in  stearine,  paraffin,  chrysene  or  naphthaline,  resin, 
or  other  like  stuffs,  the  same  having  been  dissolved  in 
benzine,  photogen,  or  other  like  solvents.  To  the  above 
may  be  added  some  carbolic  acid  or  thyme  oil.  The 
greasing  can  be  effected  as  usual.  The  new  leather  is  said 
to  be  practically  watertight,  and  when  required,  is  made 
much  softer  and  more  lasting  than  ordinary  leather,  while 
the  cost  is  stated  to  be  much  lower  than  by  the  bark 
process. 

Heinzerling's  Second  Chrome  Process — In  this  pro- 
cess the  inventor  employs  other  chrome  compounds  than 
those  mentioned  in  the  preceding  process,  as  also  certain 
other  substances  which  he  has  found  to  be  effective  in 
preparing  leather  by  his  method.  He  says,  "  I  have  found, 
too,  in  experimenting,  that  there  are  many  chrome  com- 
pounds besides  chromate  of  potash  or  magnesia  that  are 
effective.  Thus,  chromic  acid,  the  other  soluble  chromates, 
especially  those  of  ammonium,  aluminium,  and  iron,  or 
the  sulphate,  chloride,  acetate,  and  other  soluble  chromium 
salts,  are  all  efficacious  for  the  purpose  of  converting  skins 
or  hides  into  leather.  I  also  find  that  the  precipitation 
of  soft  white  neutral  mineral  material  in  the  pores  of  the 


264  LEATHER  MANUFACTURE. 

leather  is  very  advantageous  in  preserving  it,  improving 
its  colour,  and  making  it  impervious  to  moisture.  Further, 
that  the  addition  of  such  salts  or  oxides  as  the  sulphates 
of  copper,  manganese,  and  zinc,  chloride  and  borate  of 
zinc,  tungstate  of  sodium  or  of  potassium,  sulphate  or 
chloride  of  protoxide  or  sesquioxide  of  iron,  and  oxide 
of  manganese,  improve  the  texture,  durability,  and  colour 
of  the  leather."  The  inventor  then  gives  the  process  as 
actually  practised  by  him  in  Germany,  and  which  is,  we 
presume,  the  same  as  that  which  has  been  adopted  by  the 
Eglinton  Chemical  Company,  of  Glasgow. 

"  The  hides  being  unhaired  in  the  usual  manner,  I  put 
them  first  in  a  weak,  and  after  a  few  days  in  a  stronger 
solution  of  a  soluble  chromate  or  chromic  acid.  To  this 
solution  I  add  a  soluble  salt  of  aluminium,  or  the  soluble 
hydrated  oxide  which  is  formed  when  carbonate  of  soda  is 
added  to  a  solution  of  alum.  The  quantity  of  aluminous 
matter  in  solution  depends  on  the  texture  of  the  hides, 
the  density  of  leather  required,  and  the  salts  used  ;  it 
varies,  therefore,  from  nothing  to  say  four  parts  by  weight 
of  oxide  of  aluminium  to  one  hundred  of  water.  The 
quantity  of  chromium,  salt  used  varies  from  half  to  five 
parts  to  one  hundred  of  water.  In  the  first  pit  both  the 
chromic  and  aluminous  materials  are  weak,  especially  the 
latter.  While  in  succeeding  pits  the  chrome  does  not  vary 
much,  that  of  the  aluminous  matter  varies  widely,  sole  and 
other  hard  leathers  requiring  large  quantities,  whereas 
washleather  and  thin  uppers  require  none,  or  very  little. 
During  the  cold  season  the  pits  can  be  moderately  heated, 
say  30P  C.  (86°  Fahr.)  The  hides  are  left  in  this  chrome 
and  aluminous  solution,  with  or  without  the  addition  of 
any  of  the  above-mentioned  metallic  salts  useful  for  im- 
proving the  colour  or  for  tanning,  from  one  to  twenty  days, 
according  to  size,  texture,  and  thickness  of  the  hides, 
until  they  are  perfectly  converted.  Their  progress  and 
complete  conversion  may  be  easily  tested  by  cutting  off  a 
piece  and  seeing  if  the  tanning  liquor  has  thorough^ 
penetrated  it.  After  this  they  are  put  into  a  solution  of, 
say  from  three  to  eight  per  cent,  of  a  soluble  carbonate, 


CHEMICAL    TANNING.  265 

such  as  carbonate  of  sodium  or  potassium,  or  a  solution  of 
soluble  soap,  say  three  to  six  per  cent.,  in  order  to  fix  super- 
ficially the  tanning  materials.  In  some  cases  it  is  advan- 
tageous to  use,  instead  of  the  above  bath,  a  soluble  barium 
salt,  such  as  the  chloride,  especially  when  alum  or  other 
sulphates  have  been  largely  used. 

"  Instead  of  treating  the  hides  with  carbonate  of  sodium 
or  soap  in  solution,  as  before  mentioned,  in  some  cases  it 
may  be  advantageous  to  use  albuminous  matter,  such  as 
the  serum  of  blood,  either  dissolved  in  acids  or  alkalies,  or 
in  the  solid  state,  finely  divided,  as  it  is  used  in  the  kid 
leather  manufactories.  The  hides  are  either  immersed  for 
a  certain  time  till  the  matter  has  entered  superficially,  if  a 
solution  be  used,  or  tramped  in  a  tramping  tun  for  an 
hour,  in  order  to  facilitate  the  mechanical  entering  of  the 
albuminous  matter. 

"  The  hides  intended  for  upper  or  belt  leather  are  now 
dried  till  they  are  merely  damp,  and  then  stretched  ;  those 
for  sole  leather  are  made  quite  dry.  They  are  then  put 
into  a  solution  of  paraffin,  stearine,  colophony,  or  the  like 
(dissolved  in  any  suitable  solvent,  such  as  benzole  or  pho- 
togen),  or  into  vegetable  or  animal  wax,  or  such  stuff  as 
that  formed  from  treating  rape  or  linseed  oil  with  ten  to 
eighteen  per  cent,  of  chloride  of  sulphur,  or  the  solid 
soluble  residues  which  are  obtained  in  petroleum  and 
paraffin  refineries,  or  varnish  and  birch- tar  oil ;  the  above 
solution  is  heated  from  26°  to  38°  C.  (about  76°  to  100°  F.)  in 
a  water-bath  before  and  whilst  the  hides  are  in.  The  hides 
are  kept  in  this  bath  preferably  at  from  28°  to  30°  C.  (about 
86°  F.)  for  from  one  to  three  days,  according  to  size,  texture, 
and  thickness ;  they  are  then  exposed  to  the  light  for 
twenty-five  to  sixty  days,  until  the  stearine,  paraffin,  colo- 
phony, or  other  hydro-carbon  used  appears  oxidised 
throughout  Upper  and  belt  leather  can  be  greased  a 
second  time  if  required  with  the  usual  substances  or 
with  vaseline.  The  above-described  stuffs  may  be  also 
used  in  the  melted  state  if  they  are  fusible  at  a  low  tem- 
perature. 

"  After  a  certain  quantity  of  hides  have  been  tanned,  it 


266  LEATHER  MANUFACTURE. 

will  be  found  advantageous,  instead  of  adding  soluble 
aluminous  salts,  to  add  a  quantity  (proportional  to  the 
acids  set  free)  of  basic  aluminium,  compounds  got  by  in- 
complete precipitation  of  aluminium  salts  with  carbonate 
of  sodium  or  ammonium,  or  of  hydrate  of  alumina.  The 
tanning  liquor  should  be  analysed  from  time  to  time,  and 
the  mixture  kept  up  to  standard  chemical  composition." 

Vanderstraaten's  Process. — The  following  is  a  brief 
outline  of  the  process,  the  inventor  being  a  Belgian  tan- 
ner : — The  hides,  after  being  cleansed  from  all  materials 
incidental  to  the  removal  of  the  hair,  are  put  into  a  bath 
of  vegetable  tannin  of  a  certain  strength,  which  prepares 
them  for  the  succeeding  treatment.  The  bath  is  made 
from  valonia  or  similar  vegetable  substances,  and  if  twelve 
hides  are  to  be  treated  at  one  operation,  in  a  vat  holding 
about  six  cubic  metres,  five  kilogrammes  of  valonia  are 
required.  This  is  first  boiled  in  order  to  extract  all  the 
tannin.  The  hides  remain  in  this  bath  one  day,  and 
another  day  in  a  second  bath,  which  is  made  a  little 
stronger  than  the  first.  The  baths  can  be  used  over  again 
by  adding  fresh  material  until  they  are  of  the  desired 
strength.  This  first  tanning  gives  to  the  leather  an  iron- 
grey  colour.  The  second  operation  is  performed  by  means 
of  bichromate  of  potash,  which  turns  the  iron-grey 
colour  into  a  mahogany-brown.  If  a  lighter  shade  is 
desired,  half  the  valonia  of  the  first  process  is  replaced  by 
a  corresponding  quantity  of  mimosa-bark.  The  colour  of 
the  leather  can  thus  be  determined  at  the  will  of  the 
tanner  by  varying  the  quantity  of  tanning  material,  the 
strength  of  the  mixture,  and  the  time  consumed  in  the 
operation.  The  hides,  which  are  so  far  only  superficially 
tanned,  are  then  immersed  in  a  solution  of  either  alum, 
sulphate  of  silicon,  chromate  of  potash,  salts  of  iron,  or 
other  similar  astringent  agents. 

The  inventor  claims  no  right  to  any  of  the  tanning 
processes  by  minerals,  but  confines  himself  to  the  following, 
preferring  the  use  of  bichromate  of  potash  ;  the  hides  are 
immersed  in  a  weak  solution  of  this  salt,  and  frequently 
taken  out  and  turned,  so  that  the  chemical  action  which 


CHEMICAL   TANNING.  267 

produces  the  grain  and  colour  may  be  uniform.  For  this 
purpose  one  or  two  hours  are  generally  sufficient.  If  the 
operation  is  successful,  a  fine  grain,  soft  to  the  touch,  is 
formed,  and  a  moderate  swelling  can  be  seen.  The  colour 
becomes  permanent,  and  can  no  longer  be  changed.  In 
the  first  weak  bath  they  are  suspended  and  subjected  to 
a  gentle  motion  ;  here  they  remain  until  the  tanning 
material  has  thoroughly  penetrated  the  skin,  which  gene- 
rally occurs  after  from  twelve  to  fifteen  days.  The  hides 
are  then  taken  out,  thoroughly  washed,  and  subjected  to 
strong  hydraulic  pressure,  by  which  means  most  of  the 
chrome  liquor  is  forced  out  of  the  leather,  while  some  of 
it  remains,  and  this  has  to  be  rendered  insoluble,  which  is 
done  by  a  gelatine  treatment.  The  hides,  as  soon  as  they 
leave  the  press,  are  dipped  into  a  bath  of  hot  gelatine, 
made  from  the  offal  of  fresh  leather,  until  they  are 
thoroughly  impregnated  with  it,  and  after  this  are  placed 
in  an  agitator  for  about  an  hour,  by  which  time  the  gelatine 
will  have  been  absorbed  by  the  leather.  This  treatment 
renders  both  the  bichromate  of  potash  and  the  gelatine 
insoluble,  and  strengthens  the  leather  by  replacing  the 
natural  gelatine  which  had  been  extracted  in  the  earlier 
operations  of  the  process. 


CHAPTER  XXII. 
MISCELLANEOUS  PROCESSES. 

Indian  Method  of  Preparing  Elk-skins. — Old  Irish  Process  of  Tanning.— 
Tanning  Nets,  Sails,  and  Cordage. — Glycerine  in  Tanning, — Bleach- 
ing Leather. 

Indian  Method  of  Preparing  Elk-skins. — Immediately 
after  the  skin  is  removed  from  the  animal  it  is  spread  out 
to  dry.  The  brains  are  then  removed  and  also  dried  in 
the  sun  upon  the  grass.  When  the  hunting  season  is 
over,  the  women  prepare  the  hides  by  soaking  them  first 
in  water,  and  afterwards  taking  off  the  hair  with  an  old 
knife.  The  hides  are  then  put  into  a  large  earthenware 
vessel  containing  water,  and  the  brains  are  then  added 
and  the  vessel  heated  to  about  95°,  by  which  operation 
they  become  very  well  cleansed,  The  skins  are  next 
wrung  out  and  spread  upon  a  kind  of  rack  formed  of  two 
upright  posts,  with  two  sticks  placed  horizontally.  With 
the  assistance  of  ropes,  the  women  spread  them  very  well, 
and  during  the  drying  they  rub  them  continually  with  a 
stone  or  round  piece  of  wood,  to  assist  in  getting  rid  of 
the  water  and  grease,  till  they  are  quite  dry.  In  one  day 
a  woman  can  prepare  from  eight  to  ten  skins. 

Old  Irish  Process  of  Tanning. — This  consisted  in 
utilising  the  heath,  which  grows  abundantly  in  Ireland, 
as  a  tanning  material.  The  heath  was  put  into  a  large 
cauldron  full  of  water  and  allowed  to  boil  for  about  three 
hours,  by  which  time  the  tanning  principle  was  exhausted. 
The  liquor  was  afterwards  drawn  off  into  large  vats  and 


MISCELLANEOUS  PROCESSES.  269 

the  material  again  treated  with  water  as  before.  When 
this  last  liquor  had  cooled  down  to  about  95°,  the  skins 
were  first  immersed  in  this,  and  afterwards  in  liquor  of 
increasing  strength.  In  using  the  liquors  the  temperature 
should  not  exceed  95°.  A  very  good  leather  was  produced 
by  this  process. 

'Tanning  Nets,  Sails,  and  Cordage. — The  following 
method  of  preserving  and  increasing  the  strength  of  nets, 
sails,  and  cordage  was  patented  many  years  ago.  A 
hundred  pounds  of  oak  branches  and  the  same  quantity  of 
tan  are  boiled  in  eighty -nine  gallons  of  water,  until  it  is 
reduced  to  seventy-one  gallons.  The  solid  materials  are 
then  taken  out,  and  the  articles  to  be  tanned  are  deposited 
in  the  liquid,  care  being  taken  that  they  are  entirely 
covered  by  it,  and  do  not  rest  upon  the  bottom  of  the 
vessel.  They  are  boiled  for  three  hours,  and  are  then 
taken  out  and  dried.  This,  though  a  true  tanning  process, 
can  scarcely  be  likened  to  the  ordinary  ones  for  preparing 
leather,  since  its  object  is  a  combination  of  tannin  and 
extractive  matter  with  vegetable  substances,  which  are 
very  different  from  the  gelatine  of  skin.  According  to 
Millet,  linen  which  had  been  steeped  in  an  oak-bark 
liquor  at  150°  Fahr.  for  two  or  three  days,  remained 
unaltered  in  a  damp  cellar  for  ten  years,  while  an 
untanned  piece  entirely  rotted  under  similar  circum- 
stances. 

Glycerine  in  Tanning. — M.  Mene,  after  first  observing 
that  glycerine  is  a  substance  which  has  been  found  by 
experience  to  be  useful  as  a  means  of  increasing  the  elas- 
ticity and  strength  of  leather,  states  that  hides,  first  partly 
tanned  by  the  usual  process,  may  be  greatly  improved, 
especially  if  required  for  machine  belts,  by  being  soaked 
for  some  time  in  glycerine. 

Bleaching  Leather.— One  might  naturally  think  that 
when  leather  possesses  all  the  characteristics  of  solidity, 
firmness,  and  toughness,  being  perfectly  tanned  through- 
out its  entire  substance,  that  its  colour  would  be  a  matter 
of  little  concern.  That  this  is  not  so,  however,  is  well 
known,  and  any  divergence  from  the  tan  colour  proper 


270  LEATHER  MANUFACTURE. 

is  sure  to  create  a  prejudice  against  the  leather,  be  it 
ever  so  good  in  all  other  qualities.  This  is  specially  so 
in  the  case  of  hemlock-tanned  leather,  which,  unless  pre- 
pared with  more  than  ordinary  care,  or  combined  with 
other  tanning  materials  to  reduce  its  natural  redness, 
presents  a  colour  which,  in  the  eyes  of  those  accustomed 
to  the  colour  of  oak-tanned  leather,  is  objectionable  in 
the  extreme.  To  overcome  this  well-known  prejudice 
against  hemlock  tannage,  many  ingenious  persons  have 
turned  their  attention,  with  the  result  that  certain 
Ueacliing  processes  have  been  introduced  into  the  United 
States,  for  the  details  of  which  we  are  indebted  to 
Mr.  Jackson  Schultz,  who,  however,  does  not  commend 
this  system  of  tampering  with  leather  in  the  processes  of 
finishing. 

By  one  process  of  bleaching  sugar  of  lead  and  sulphuric 
acid  are  employed.  "The  practice  is  to  dip  the  sides 
alternately,  first  into  the  bath  of  the  one  and  then  into 
the  other,  until  the  colouring  matter  of  the  hemlock  is 
fully  removed.  This  bleaching  process  gives  an  imme- 
diate, that  is  almost  magical,  result ;  but  when  the  finished 
leather  is  exposed  to  the  air  and  light  for  any  considerable 
time,  the  delicate  pink  and  cream  colour  turns  to  a '  murky 
brown/  and  is  in  all  respects  a  most  objectionable  finish. 
The  only  natural  and  honest  bleaching  process  known  to 
the  writer  is  that  of  '  sumac  baths.'  Alter  the  hemlock 
sides  have  been  cleansed  of  all  extraneous  matter  by  the 
most  effective  mechanical  device  known,  they  must  then 
be  hung  in  a  vat  of  warm  sumac  liquor,  and  plunged  fre- 
quently for  one  day — even  a  few  hours  will  sensibly  affect 
the  colour.  Usually  one  bag  of  Virginia  sumac  will 
suffice  for  a  pack  of  one  hundred  sides.  This  process  will 
cost  about  five  dollars  for  a  pack,  or  five  cents  per  side 
weighing  15  Ibs.  to  20  Ibs.  The  sumac  liquor  forms  a 
vegetable  acid,  which  acts  most  kindly  on  the  grain  of 
hemlock  slaughter  leather,  not  only  removing  (neutra- 
lising) the  colour,  but  softening  the  grain,  and  contributes 
very  much  to  the  whiteness  and  clearness  of  the  buff." 
Mr.  Schultz  says  that  hemlock  leather  thus  treated  will 


MISCELLANEOUS  PROCESSES.  271 

retain  the  improved  colour  for  a  long  time,  and  "  never  go 
back  to  that  muddy  and  objectionable  colour  so  common 
with  other  bleaching  processes." 

"  As  it  is  the  acid  which  effects  the  object  sought,"  Mr. 
Schultz  observes,  "  the  sumac  should  be  retained  long  after 
the  tannin  has  departed.  As  a  mere  tanning  agent  it  is 
only  valuable,  as  all  goat  and  sheep  skin  tanners  compre- 
hend, while  it  is  fresh,  and  before  the  acid  forms.  But  for 
the  purpose  of  bleaching  hemlock  leather  it  is  questionable 
whether  the  old  cast-off  sumac  of  the  morocco  dresser  is 
not  quite  as  valuable  as  new  sumac."  To  this  Mr.  Schultz 
adds  an  important  suggestion  which  the  users  of  hemlock 
will  doubtless  appreciate.  "  Slaughter  hemlock  leather, 
tanned  with  liquors  of  moderate  strength,  say  16°  to  20°, 
will  produce  a  colour  that  is  between  the  lemon  and  the 
orange,  and  if  to  this  we  add  the  warm  sumac  process,  we 
have  then  a  colour  so  nearly  a  light  lemon  or  flesh  colour 

as  to  meet  all  the  requirements  of  the  best  oak 

This  process  is  particularly  serviceable  on  calf  and  all 
grain-finished  leathers,  including  harness  and  bridle.  No 
hemlock  tannages  will  'take  the  bleaching'  so  well 
without  as  with  this  process.  With  it  grain  leather  can 
be  made  to  hold  its  colour  almost  equal  to  a  pure  oak 
tannage." 

NOTE. — Sumac  is  still  used  extensively  for  bleaching  purposes.  Care 
must,  however,  be  used  in  its  application,  otherwise  the  leather  so 
treated  is  likely  to  lose  weight.  Sumac  appears  to  possess  the  property 
of  being  able  to  dissolve  and  withdraw  some  of  the  more  solid  con- 
stituents of  the  previous  tannins  used. — ED.  Fifth  Edition. 


CHAPTEE  XXIII. 
ON  THE  COST   OF  AMERICAN  TANNING. 

Mr.  J.  Sclmltz  on  the  Cost  of  Tanning — This  obser- 
vant American  authority  has  entered  very  fully  into  the 
question  of  the  cost  of  tanning,  and  with  his  usual  clear- 
ness of  reasoning  has  shown  how  variable  may  be  the 
results  obtained  by  manufacturers  working  under  different 
conditions  or  by  different  methods  of  tanning.  He  ap- 
proximately estimates  the  cost  of  tanning  as  follows  : — 

Hemlock  sweat  sole  leather per  Ib.  from  6  to  7  cents. 

Union  lime  sole  leather „          „     8  „  9      „ 

Oak  lime  leather „          ,,     9  „  10    ,, 

Oak  lime  rough  leather „          „     8  „  9      „ 

Hemlock  lime  rough  leather....       „          „     6  „  7      ,, 

The  cost  will  differ  with  the  circumstances  under  which 
the  tanning  is  conducted.  One  tanner  devotes  extra 
time  to  the  beam  work  ;  another  to  the  finishing ;  an- 
other to  the  handlers  or  layers ;  the  freight  and  price 
of  bark  will  vary  in  different  localities,  therefore  in  esti- 
mating the  cost  it  is  to  be  understood  that  an  average  is 
given. 

One  ton  (2,240  Ibs.)  of  average  hemlock  bark  will  tan 
200  Ibs.  of  sole  leather,  with  the  following  exceptions  : — 
1.  If  the  bark  is  ground  and  leached  imperfectly,  or  in 
an  extraordinarily  perfect  manner;  2.  If  the  leather  is 
tanned  with  a  very  strong  decoction,  and  thereby  a  very 
large  gain  is  obtained  as  against  very  weak  liquors  and 
light  gain ;  3.  Great  delays  and  wastes  in  applying  the 
tannin,  which  induce  the  formation  of  gallic  acid ;  or  the 


COST  OF  AMERICAN  TANNING.  273 

bringing  fresh,  sweet,  strong  decoctions  into  contact  with 
liquor  already  containing  a  large  percentage  of  this  acid. 
These  exceptions  will  vary  the  result  from  180  Ibs.  to 
200  Ibs.  of  leather  made  from  one  ton  of  bark.  Again,  if 
the  weight  of  the  delivered  bark  is  not  accurate  a  loss 
will  accrue  from  this  cause. 

Mr.  Schultz  attaches  great  importance  to  the  strength  of 
the  liquors  employed,  as  influencing  the  cost  of  tanning. 
He  says :  "  The  upper  leather  tanners  of  New  England, 
who  pay  ten  to  twelve  dollars  per  cord  [or  ton]  for  their 
bark,  claim  to  tan,  and  probably  do  tan,  from  300  Ibs.  to 
400  Ibs.  of  upper  leather  with  2,240  Ibs.  of  bark.  If  we 
comprehend  how  this  is  possible,  it  will  enlighten  us  as  to 
the  point  under  discussion.  The  upper  leather  tanners 
draw  their  tanning  and  colour  matter  from  agents  which 
furnish  about  20  per  cent,  extractive  material,  while  the 
vigorous  sole  leather  tanner  obtains  his  capital  from  the 
7  to  8  per  cent,  tannin  which  the  bark  contains.  The 
tannin  gives  all  the  gain  added  to*  the  gelatine,  but  the 
colouring  matter  permeates  the  fibre,  while  cumulative 
gallic  acid  holds  it  from  decomposition.  Upper  leather, 
then,  is  not  tanned  and  filled  as  sole  leather  is,  and 
to  this  extent  and  for  this  reason  bark  extract  will 
spread  itself  over  far  more  fibre  when  all  the  extractive 
matter  is  employed  than  when  it  is  manufactured  so  as  to 
hold  only  tannin  pure  and  simple.  It  must  be  evident 
that  when  skins  are  tanned  quickly  in  strong  liquors  it  is 
at  the  expense  of  the  most  costly  agent  (the  tannin), 
while  the  vegetable  extractive  (the  cheaper  material)  does 
not  enter  the  skin  to  any  appreciable  extent.  Conse- 
quently, if  we  are  to  accept  Davy's  view,  the  leather 
produced,  while  being  extravagantly  filled  with  tannin, 
will  be  deficient  in  one  of  its  most  important  constituents 
(extractive),  and  therefore  inferior  in  quality  and  of  less 
value  than  leather  which  is  tanned  by  slower  methods. 
....  If  upper  leather  and  calf  skins  are  to  be  sold 
by  the  pound  (waiving  the  question  of  quality,  especially 
toughness),  then  it  is  evident  that  these  light  tannages 
cannot  be  afforded.  But  if  sold  by  measure,  then  a  light 

T 


274  LEATHER  MANUFACTURE. 

tannage  is  profitable  to  both  tanner  and  consumer  under 
proper  circumstances." 

The  above  observations  are  introduced  to  solve  the  ques- 
tion whether  a  sole  leather  tanner  who  tans  by  the  pound 
can  afford  to  make  heavy  gains  for  his  employer.  One 
tanner  makes  160  Ibs.  and  another  170  Ibs.  of  leather  from 
100  Ibs.  of  hides,  "Are  they,"  asks  Mr.  Schultz,  "entitled 
to  the  same  pay  per  pound  ?  Is  the  cost  to  each  propor- 
tionate ?  The  argument  on  the  one  side  is  as  follows : — 
It  costs  a  certain  sum  to  work  in,  handle,  and  finish  a 
given  lot  of  leather,  whether  of  heavy  or  light  tannage ; 
the  cost  of  the  bark  being  alone  considered,  it  cannot 
exceed,  and  most  usually  falls  short  of,  the  price  received 
for  tanning,  even  though  the  price  be  as  low  as  six  cents 
per  pound.  The  sole  leather  problem  is  then,  in  fact,  but 
the  upper  leather  question  over  again,  which  would  ask 
and  determine  the  following :  Can  a  customer  afford  to  tan 
rough  leather  for  less  per  pound  than  sole  leather,  less  the 
finishing  ?  "  He  does  not  consider  it  an  answer  to  say 
that  they  do  tan  it  for  less,  or  that  small  tan-yards,  with- 
out much  interest  to  pay,  pursue  the  trade  successfully, 
while  the  argument  on  the  other  side  is  that  "heavy  gains 
cannot  be  made  with  strong  decoctions ;  strong  liquor  can- 
not be  obtained  unless  more  or  less  waste  is  permitted— 
waste  in  the  liquor  itself,  and  more  strength  lost  in  leach- 
ing. Besides,  the  actual  net  added  weight  costs  more  than 
is  received,  which  is  calculated  as  follows  : — 

Original  weight  of  hide 100  Ibs. 

Less  hair,  grease,  fat,  &c 15    „ 

Net  gelatine  and  animal  fibre 85  Ibs. 

"Now,  whether  this  product  is  raised  to  160  Ibs.  or 
175  Ibs.  is  a  question  of  mere  intrinsic  cost  of  the  pure 
tannin,  which  is  capable  of  combining  with  the  gelatine. 
In  the  one  case  75  Ibs.  is  required,  and  in  the  other  90  Ibs. 
The  cost  of  these  respective  factors  made  from  bark  at 
six  dollars  per  cord  would  be  (on  the  theory  on  which  we 
are  proceeding)  fully  eight  cents  per  pound,  since  in  both 
cases  we  start  with  the  hide  capital  of  85  Ibs.  It  may  be 


COST  OF  AMERICAN  TANNING.  275 

assumed  that  there  is  a  discrepancy  between  the  theoretical 
and  practical  percentage  of  tannin  obtainable  from  bark. 
We  know  that  2,240  Ibs.  of  hemlock  bark  will  make  only 
200  Ibs.  of  leather.  Chemists  tell  us,  however,  that  there 
is  8  per  cent,  of  tannin  in  this  bark,  consequently  there 
is  in  this  ton  of  bark  156  80-100  Ibs.,  which,  combined  with 
85  Ibs.  of  gelatine,  should  give  241  80-100  Ibs.  of  leather 
[without  reckoning  the  vegetable  extractive  ?].  What  has 
become  of  this  71  Ibs.  of  lost  tannin?  " 

May  we  not  venture  to  suggest  that  while  a  consider- 
able proportion  of  the  lost  tannin  is  converted  into  gallic 
acid,  a  further  portion  is  exhausted  (especially  when  the 
liquors  are  made  with  hot- water)  by  combining  with  the 
fibre  of  the  bark — tanning  it,  in  fact  ? 

Mr.  Schultz  gives  the  following  as  the  probable  cost  of 
each  item  in  the  production  of  hemlock  leather  : — 

Cost  of  bark  (hemlock)  per  Ib 3  cents. 

Cost  of  soaking,  milling,  sweating  and  beam  work  ....  1  cent. 

Yard  work,  including  handling,  laying  away,  &c ^    „ 

Finishing,  including  drying,  rolling,  &c \    ,, 

Insurance,  interest  on  tanning  and  bark \    ,, 

Freight  to  and  from  the  market 1  ~    ,, 

Administration £    n 

Total . .  7  centa. 


CHAPTER  XXIV. 
MANUFACTURE   OF  LIGHT  LEATHERS. 

Russia  Leather. — Count  Kartstoff's  Description  of  Russia  Leather  Manu- 
facture.— Smoking  Skins. — Another  Method  of  Preparing  Russia 
Leather. — Black  Russia  Leather. — Yults  Russia  Leather. — Morocco 
Leather. — Sumao  Tanning. — Imitation  Morocco  Leather. — Skiver. — 
Cordovan  Leather. — Roan.— Hungary  Leather. — Wallachia  Leather. 
— Barley  Dressing  — Morfit's  Remarks  on  White  Dressing. — Red 
Dressing. — Bran  Dressing. — Enamelled  Leather. 

Russia  Leather. — The  peculiar  characteristics  of  this 
famous  leather  have  won  for  it  almost  universal  admi- 
ration. Its  agreeable  perfume,  which,  like  the  Tonquin 
bean,  it  communicates  to  other  objects  placed  in  contact 
with  it;  its  resistance  to  damp,  which  fails  to  produce 
that  mouldiness  or  vegetable  growth  to  which  most 
leathers  are  subject  under  such  conditions ;  and  the  well- 
known  fact  that  insects  are  repelled  even  by  its  odour,  have 
combined  to  maintain  the  popularity  of  this  agreeable 
leather.  Although  it  is  generally  understood  that  the 
true  secret  of  its  manufacture  has  been  jealously  guarded 
by  those  whose  interest  it  is  to  keep  it  from  the  public,  the 
process,  more  or  less  accurate,  has  from  time  to  time  been 
made  known  by  various  writers.  The  process,  as  given 
by  Ure,*  is  as  follows  : — 

"  The  skins  are  freed  from  the  hair  or  fleece  by 
steeping  in  an  ash  ley  too  weak  to  act  upon  the  animal 
fibres.  They  are  then  rinsed,  fulled  for  a  longer  or 
shorter  time,  according  to  their  nature,  and  fermented 
in  a  proper  steep,  after  having  been  washed  in  hot 

*  "  Dictionary  of  Arts,  Manufactures,"  &c. 


LIGHT  LEATHERS.  277 

water.  They  are  taken  out  at  the  end  of  a  week ;  but 
they  may  be  steeped  a  second  time,  if  deemed  necessary, 
to  open  their  pores.  They  are  now  cleaned  by  working 
them  at  the  horse  [or  beam]  on  both  flesh  and  grain  sides. 
A  paste  is  next  composed,  for  200  skins,  of  38  Ibs.  of 
rye-flour,  which  is  set  to  ferment  with  leaven.  This 
dough  is  worked  up  with  a  sufficient  quantity  of  water  to 
form  a  bath  for  the  skins,  in  which  they  arc  soaked  for 
forty-eight  hours ;  they  are  then  transferred  to  small 
tubs,  where  they  remain  during  fifteen  days,  after  which 
they  are  washed  at  the  river.  These  operations  serve  to 
prepare  the  skins  for  absorbing  the  astringent  juices  with 
uniformity.  A  decoction  of  willow-bark  (Salix  cincrca 
and  S.  caprca)  being  made,  the  skins  are  immersed  in  the 
boiler  whenever  the  temperature  of  the  liquor  is  suffi- 
ciently lowered  not  to  injure  the  animal  fibres,  and 
handled  and  pressed  for  hali-an-hour.  The  manipulation 
is  repeated  twice  daily  during  the  period  of  a  week.  The 
tanning  infusion  is  then  renewed,  and  applied  to  the 
same  skins  for  another  week,  after  which,  being  exposed 
to  the  air  to  dry,  they  are  ready  for  being  dyed,  and  then 
curried  with  the  empyreumatic  oil  of  the  bark  of  the 
birch-tree.  To  this  substance  the  Russia  leather  owes  its 
peculiarities.  The  skins  imbibe  this  oil  most  equally 
before  they  are  fully  dry.  Care  must  be  taken  not  to 
apply  too  much  of  it,  for  fear  of  its  passing  through  and 
staining  the  grain  side  of  the  leather."  The  red  colour 
of  Russia  leather  is  supposed  to  be  produced  by  Saunders- 
wood  or  Brazil-wood. 

Count  Kartstoff's  Description  of  Russia  Leather 
Manufacture. — In  a  memoir  published  by  Count  Karts- 
toff,  the  following  description  of  Russia  leather  tanning  is 
given : — "  The  dried  skins  are  softened  by  soaking  in 
water  for  five  or  six  days  in  summer  and  ten  or  twelve 
days  in  winter,  and,  after  being  well  cleaned,  are  deprived 
of  hair  by  steeping  in  milk  of  lime — 185  Ibs.  being 
mixed  with  water  in  a  vat  eight  feet  in  diameter  and  seven 
feet  eight  inches  high.  The  skins  are  frequently  ex- 
amined, and  when  the  epidermis  and  hairs  give  readily, 


278  LEATHER  MANUFACTURE. 

they  are  carefully  unhaired  upon  the  beam  and  then 
fleshed.  Stout  hides  are  not  limed,  but  exposed  in  a 
sweating-room,  piled  upon  each  other,  and  sprinkled  with 
salt  to  prevent  decomposition ;  bran  baths  are  used  for 
the  same  purpose  for  thin  and  delicate  skins.  The  skins, 
after  being  limed,  are  well  soaked,  washed,  beaten  out 
with  the  feet,  and  rinsed  in  warm  water  until  the  last 
portions  of  the  lime  have  been  removed  from  them  ;  they 
are  then  raised  by  steeping  for  forty-eight  hours  or  more 
in  a  vat  of  the  above  dimensions,  containing  a  fermented 
mixture  of  warm  water  with  1,100  Ibs.  of  ryemeal,  or 
450  Ibs.  of  oatmeal,  6  Ibs.  of  salt,  and  a  sufficient  quantity 
of  leaven.  Being  thus  prepared  for  tanning,  they  are 
steeped  for  a  time  in  a  weak  infusion  of  oak  or  willow 
bark,  the  latter  being  preferred,  and  are  then  stratified  in 
a  vat  with  la}^ers  of  coarse  bark,  the  vat  being  filled 
up  with  the  tanning  infusion  first  used,  and  its  contents 
beiug  pressed  down  with  planks,  heavily  weighted  with 
stones. 

"  The  skins  are  left  in  this  vat  from  fifteen  to  twenty- 
eight  days,  after  which  they  are  removed  and  again 
stratified  with  fresh  bark.  This  operation  is  repeated 
from  three  to  six  times,  according  to  the  nature  and 
quality  of  the  skins,  the  thinnest  kinds  only  requiring 
two  changes.  The  stiffness  acquired  by  the  leather  in 
tanning  is  then  corrected  by  soaking  them  for  a  day  or 
two  in  a  paste  composed  of — for  every  150  skins  of 
ordinary  size — 130  Ibs.  of  oatmeal  and  9  Ibs.  of  salt, 
mixed  with  warm  water.  The  leather  is  then  well 
washed,  rinsed,  and  drained,  and,  while  in  a  partially 
moist  state,  is  placed  upon  a  large  table,  flesh  side  up,  and 
coated  with  oil.  This  is  composed  of  a  mixture  of  the  oil 
obtained  from  sea-calves  (which  abound  in  the  Caspian 
Sea)  and  of  the  pure  oil  or  tar  of  birch-bark  in  varied 
proportions,  according  to  the  nature  and  quality  of  the 
leather,  one  part  of  the  latter  to  two  parts  of  the  former 
being  generally  used.  The  workman  spreads  the  mix- 
ture with  his  hand  evenly  and  uniformly  over  the  surface, 
and  the  perfection  of  this  operation  depends  upon  the 


LIGHT  LEATHERS.  279 

skill  with  which  it  is  done.  About  nine  ounces  of 
oil  are  applied  to  each  skin  of  medium  size.  \Vhen 
oiled,  the  leather  is  then  stretched  out  upon  cords  in  an 
open  shed  until  perfectly  dry,  and  in  the  winter  season 
is  exposed  to  the  cold  air,  by  which  its  appearance  is  much 
improved." 

Smoking  Skins. —  The  Baskirs  and  Kerguises  pre- 
pare their  skins  by  smoking  in  lieu  of  tanning  them. 
They  first  stretch  them  out,  in  their  green  state,  between 
stakes  fixed  in  the  ground,  and  then  remove  the  hair  by 
scraping  with  a  broken  sickle  fixed  in  a  wooden  handle. 
They  then  dig  a  pit  in  the  ground,  proportioned  in  size 
to  the  number  of  skins  to  be  operated  upon,  and  suspend 
them  across  parallel  cords  which  are  attached  to  its  edges. 
A  round  hole  is  then  dug  five  feet  from  the  edge  of 
the  pit,  and  is  connected  with  it  by  a  subterranean  gutter. 
The  skins  are  hung  upon  the  cords,  the  pit  is  covered 
over,  and  a  fire  of  dry  rotten  wood  is  lighted  in  the  small 
hole,  the  top  of  which  is  then  closed.  The  smoke  then 
passes  through  the  connecting  gutter  into  the  pit,  and  the 
skins  are  kept  exposed  to  its  action  for  two  or  three 
weeks,  at  the  end  of  which  time  they  are  found  to  have 
acquired  properties  similar  to  those  of  leather,  and,  above 
all,  a  degree  of  impermeability  which  does  not  exist  in 
that  which  is  tanned.* 

Another  Method  of  Preparing  Russia  Leather. — 
This  method,  described  by  Venables,  is  carried  out  as 
follows :  —  The  whitest  and  most  perfect  skins  being 
selected,  are  first  soaked  in  water,  then  scraped  upon  the 
beam,  fulled,  worked  with  the  pommel,  and  then  oiled 
upon  the  hair  side  with  pure  fish-oil,  and  upon  the  flesh 
side  with  a  mixture  of  oil  and  train-oil  scourings.  When 
dry  they  are  again  pommeled,  washed  over  upon  the  hair 
side  with  a  solution  of  alum,  and  then  pressed  under  the 
cylinder.  This  cylinder,  by  which  the  diamond-shaped 
grain  is  given  to  Russia  leather,  is  made  of  steel ;  it  is 

*  It  is  more  than  probable  that  this  primitive  method  of  curing  skins 
was  practised  in  the  earliest  ages,  many  centuries  before  the  tanning  pro- 
perties of  plants  were  known.— A.  W. 


28o  LEATHER   MANUFACTURE. 

about  twelve  and  a  half  inches  long  and  three  inches  in 
diameter,  and  is  covered  with  a  number  of  close  parallel 
threads  or  grooves,  like  those  of  a  screw,  but  cut  perpen- 
dicular to  its  axis,  and  not  spirally.  The  cylinder  is 
filled  with  stones,  and  is  moved  in  two  directions  upon  a 
wooden  bench  or  support  by  means  of  a  cord  passing 
round  a  wooden  roller  with  a  handle.  This  cord  passes 
also  over  two  cylinders  attached  to  the  floor  and  a  fourth 
one  upon  the  edge  of  the  bench.  The  cylinder  having  the 
handle  upon  its  axle  is  divided  into  two  different  parts, 
over  which  the  two  extremities  of  the  cord  pass  in  dif- 
ferent directions,  so  that  two  opposite  movements  can  be 
given  to  the  cylinder  by  one  handle. 

The  cylinder  is  sustained  and  directed  by  iron  bars 
placed  along  the  bench  upon  which  it  rolls.  The  skin 
which  is  to  be  grained  is  placed  below  it  lengthwise  upon 
the  bench,  and  longitudinal  grooves  are  pressed  upon  its 
surface  by  the  track  of  the  cylinder.  The  skin  is  then 
removed,  and  again  placed  upon  the  bench,  either  cross- 
wise or  at  an  angle,  according  as  it  is  intended  to  give  it 
a  square  or  a  diamond-shaped  grain.  When  properly 
grained,  a  second  soak  of  alum-water  is  applied,  and  when 
nearly  dry  the  Russian  oil  is  spread  over  the  grain  side, 
and  the  red  or  black  colour  is  given.  The  skin  is  then 
repeatedly  exposed  for  a  short  time  to  the  direct  rays  of 
a  hot  sun,  until  the  colour  has  sufficiently  penetrated  its 
substance,  when  it  is  fulled,  pommeled,  sleeked  with  the 
round  knife,  upon  the  beam,  and  finally,  well  rubbed 
upon  the  hair  side  with  a  hard  brush.  The  chief  charac- 
teristic of  the  preparation  of  Russia  leather  is  its  impreg- 
nation with  the  birch-bark  oil,  the  mode  of  preparing 
which  is  still,  in  a  measure,  kept  secret.  In  order  that 
the  oil  should  penetrate  the  leather  properly,  the  latter 
must  not  be  either  too  moist  or  too  dry,  but  should  contain 
just  sufficient  water  to  enable  the  oil  to  spread  equally 
over  the  surface,  and  be  absorbed  in  proportion  as  the 
moisture  gradually  evaporates.  Thus  prepared,  the  leather 
retains  the  characteristic  odour  for  a  long  time.  Great 
care  should  be  taken  not  to  apply  an  excess  of  the  oiL 


LIGHT  LEATHERS.  281 

From  12  ozs.  to  1  Ib.  generally  suffice  for  fully  impreg- 
nating a  large  cow-skin.  In  the  case  of  leather  not  dyed, 
or  of  Morocco  to  which  it  may  be  desired  to  impart  the 
odour,  only  a  very  small  portion  should  be  applied  to  the 
flesh  side.  The  composition  of  the  red  colour  with  which 
llussia  leather  is  commonly  stained  has  not  been  accu- 
rately ascertained.  It  usually  contains  Brazil-wood,  alum, 
Mild  some  other  ingredients.  It  is  not  very  durable,*  and 
does  not  resist  the  action  of  boiling  water  or  of  potassa, 
though  it  generally  remains  unaltered  in  the  air.  Other 
dyes  of  better  quality  are  sometimes  used,  which  enhance 
the  price  of  the  leather. 

Black  Russia  Leather  is  prepared  in  the  same  way 
as  the  other,  and  is  stained  by  repeated  applications  of 
the  acetate  of  iron. 

Yufts,  or  Youfts  Russia  Leather. — Wagner  describes 
the  method  of  preparing  this  leather,  the  name  of  which 
is  derived  from  the  Russian  word  yitfte,  signifying  a  pair, 
because,  as  it  is  supposed,  the  hides  are  sewn  together  in 
pairs  previous  to  the  process  of  tanning.  The  hides 
usually  prepared  for  leather  in  Russia  are  those  of  young 
cattle  ;  sometimes,  however,  the  hides  of  horses  and  skins 
of  sheep,  goats,  and  calves  are  employed.  The  operations 
for  preparing  yufts  are — 1.  Cleaning  of  the  hides  with 
lime  as  usual.  2.  Swelling  or  raising  in  a  bath  of  sour 
wheat  liquor,  exhausted  tan  liquor,  or  mixture  of  dog's 
dung  and  water.  3.  Tanning  with  various  kinds  of 
willows,  fir  and  birch  bark  being  also  used.  The  pelts  are 
first  treated  for  some  days  in  partly  exhausted  bark,  and 
are  next  put  into  tanning  tanks,  along  with  bark,  or 
sometimes  into  a  warm  infusion  of  the  tanning  materials. 
The  tanning  occupies  from  five  to  six  weeks.  4.  The 
tanned  hides  are  placed  on  the  planing  block  to  drain, 
and  are  next  impregnated  with  oil  of  birch.  The  oil  is 
rubbed  into  the  hides  on  the  flesh  side,  and  when 
thoroughly  impregnated  the  hides  are  stretched  until 

*  In  %ome  specimens  of  Russia  leather  binding  in  the  Patent  Office 
Library,  London,  not  only  has  the  colour  faded,  but  the  leather  appears 
to  be  undergoing  a  process  of  decay.— ED.  Fifth  Edition. 


282  LEATHER   MANUFACTURE. 

they  become  soft  and  supple  ;  they  are  next  rubbed  on  the 
grain  side  with  a  solution  of  alum,  and  then  grained  and 
dried.  The  dry  hides  are  dyed  in  pairs,  sewn  together  in 
the  form  of  a  bag,  into  which  the  dye  material  is  poured. 
"When  a  red  colour  is  desired,  the  dye  is  prepared  from 
sandal-wood,  with  the  addition  of  potash  or  soda.  By 
more  recent  methods,  the  hides  are  dyed  by  being 
brushed  over  five  or  six  times  with  the  dyeing  material. 
After  dyeing,  the  leather  is  dressed  in  the  usual  way. 

Oil  of  Birch. — The  oil  of  birch  employed  in  the  pre- 
paration of  Russia  leather  is  obtained  by  dry  distillation. 
The  whitish  membranous  epidermis  of  the  birch,  stripped 
of  its  woody  matter,  is  placed  in  a  copper  still,  to  which 
is  connected  a  pipe  for  conducting  the  volatile  products  to 
a  receiver  containing  cold  water.  About  60  per  cent,  of 
the  weight  of  the  bark  is  in  this  way  obtained  in  the 
form  of  a  crude  oil. 

Chevreul  investigated  the  chemical  nature  of  the  oil  of 
birch,  and  found  that  its  odoriferous  property  is  due  to 
a  peculiar  compound,  to  which  he  has  given  the  name  of 
betuline  from  betula,  the  birch-tree. 

Morocco  Leather. — Not  less  famous  than  the  leather 
just  noticed  is  that  known  as  Morocco  leather.  Unlike 
the  former,  however,  this  kind  of  leather  is  very  exten- 
sively manufactured  both  in  this  country  and  on  the  Con- 
tinent, and  forms  an  important  branch  of  industry  with 
the  manufacturers  of  light  and  fancy  leathers.  True 
Morocco  leather  is  goat  skin  tanned,  and  dyed  on  the  grain 
side.  The  skins  of  sheep,  however,  are  extensively  em- 
ployed for  conversion  into  a  cheaper  variety  of  this 
leather,  and  are,  after  tanning,  dyed  in  a  great  number  of 
different  colours. 

Morocco  leather  prepared  from  goat  skins  is  exten- 
sively used  for  carriage-linings,  chair-covers,  for  superior 
bookbinding,  pocketbooks,  purses,  and  many  other  useful 
purposes.  This  leather  is  remarkable  for  its  glossy, 
wrinkled,  and  fibrous  appearance.  The  goat  skins  from 
which  Morocco  leather  is  manufactured  in  England  are 
largely  imported  from  Switzerland,  the  East  Indies,  Cape 


LIGHT  LEATHERS.  283 

of  Good  Hope,  Memel,  Mogadore,  Asia  Minor,  Germany, 
and  other  parts  of  the  world.  The  skins  vary  con- 
siderably in  size  and  thickness,  as  also  in  quality,  and  are 
imported  with  the  hair  on. 

An  important  feature  in  the  preparation  of  Morocco 
leather  is  the  tanning  process,  which  is  effected  with 
sumac  in  a  very  peculiar  way,  as  will  be  explained 
further  on.  The  goat  skins  are  first  soaked,  or  drenched, 
in  water  for  several  days,  to  soften  them,  and  are  next 
broken — that  is  scraped  or  rubbed  on  the  beam,  on  the 
flesh  side,  to  further  soften  them  and  to  remove  flesh}* 
matters  which  would  interfere  with  the  action  of  the  lime 
liquor  to  which  they  are  afterwards  subjected.  They  are 
then  placed  in  old  lime  liquor  for  two  or  three  days,  after 
which  they  are  handled  or  "  drawn,"  by  removing  them 
from  the  pits  by  means  of  small  tongs  (Fig.  48),  and 


Fig.  48. 

placing  them  in  a  heap  for  a  few  hours.  They  are  next 
transferred  to  a  "  middling  "  lime  liquor  for  several  days, 
being  frequently  drawn  as  before,  and  the  skins  are  finally 
placed  in  pits  containing  strong  lime  liquor,  in  which 
they  are  allowed  to  remain  with  frequent  handling  or 
"  drawing,"  until  the  epidermis  readily  yields  to  the 
touch.  The  liming  generally  occupies  from  about  ten  to 
fourteen  days  in  summer,  but  in  winter  a  longer  period 
is  required. 

Unhairing  and  Fleshing. — The  goat  skins,  when  ready 
for  unhairing  and  fleshing,  are  removed  to  the  fleshing 
shop,  or  beam  house,  in  which  a  series  of  beams,  placed  at 
equal  distances  from  each  other,  are  arranged  opposite  the 
windows  of  the  apartment,  whereby  the  workmen  are 
enabled  to  perform  their  operations  in  a  good  light.  Each 
goat  skin  is  laid  smoothly  on  the  beam,  with  the  hair  side 
upward,  and  the  beam  man,  standing  behind  the  beam, 
scrapes  the  hair  from  the  pelt  by  means  of  the  two-handled 
unhairing  knife.  Fig.  49  illustrates  the  operation.  After 


284 


LEATHER  MANUFACTURE. 


being  unhaired  the  goat  skins  are  again  steeped  in  lime 
liquor  for  two  or  three  days,  after  which  they  are 
fleshed  on  the  beam.  The  lengthened  steepings  in  the 
lime-pits  naturally  cause  the  lime  to  enter  into  the  pores 
of  the  skin,  and  therefore  its  entire  removal  is  the  next 
most  important  step,  so  that  the  tanning  principle  of  the 
sumac  may  fully  enter  into  the  fibrous  structure  of  the 
pelt.  For  this  purpose  a  mixture  composed  of  dogs' 
clung  and  water  is  employed.  This  mixture,  called  the 
pure,  is  of  an  alkaline  nature,  and  has  the  effect  of  convert- 


Fig.  49. 

ing  the  lime  within  the  pores  of  the  skins  into  soluble  salts, 
which  eventually  become  removed  by  washing  and  the 
mechanical  processes  of  scraping  or  scudding.  A  great 
many  attempts  have  been  made  to  provide  a  less  disagree- 
able substitute  for  the  excrement  of  dogs,  but  the  fact 
that  this  material  is  still  extensively  used,  especially  in 
England,  would  indicate  that  as  yet  no  efficient  substitute 
has  been  found. 

Scudding. — After  remaining  in  the  pure  for  some  time, 
the  skins  are  removed,  and  after  being  steeped  they  are 


LIGHT  LEATHERS.  285 

forcibly  scraped,  or  scudded,  as  it  is  termed,  with  a  blunt 
two-handled  knife,  both  on  the  grain  and  flesh  side,  by 
which  the  remaining  lime  and  albuminous  matters  are 
forced  out  of  the  pelt.  They  are  then  again  steeped  for  a 
short  time,  and  the  effect  of  the  various  operations  to  which 
they  have  been  submitted  is  that  the  pores  of  the  skins  are 
opened  and  free  from  all  such  matters  as  would  prevent  the 
proper  absorption  of  the  tanning  principle. 

Sumac  Tanning.  —  The  peculiar  nature  of  this  tanning 
material,  which  is  of  a  yellow  colour,  renders  it  necessary 
to  apply  it  in  such  a  way  that  its  action  upon  the  pelts 
shall  be  perfectly  uniform,  a  result  which  would  not  be  at- 
tained if  the  skins  were  immersed  in  an  infusion  of  the 
material  in  the  same  way  as  in  ordinary  bark  tanning.  In 
order,  therefore,  to  insure  perfect  uniformity  in  the  action 
of  the  sumac  tannin,  the  following  system  is  adopted  :— 
The  pelts,  after  passing  through  the  various  operations 
above  described,  are  transferred  to  an  apartment  in  which 
they  are  sewn  up  into  bags  by  women — each  skin  forming 
a  bag — with  the  grain  side  outward,  a  small  opening  at 
the  hinder  part  only  being  left  for  the  introduction  of  a 
funnel.  At  Messrs.  Bevingtons'  Bermondsey  wo'ks  these 
bags  are  now  made  by  the  sewing-machine.  When  the 
bags  are  made  they  are  thrown  into  a  vessel  of  water  and 
examined  to  ascertain  if  they  are  properly  sewn  and  free 
from  holes.  They  are  next  taken  to  the  sumac  tub,  which 
is  a  large  shallow  vessel  about  fifteen  feet  in  diameter, 
and  which  is  filled  with  hot  water  containing  a  little 
sumac.  Close  to  this  tub  is  a  smaller  vessel  containing 
a  strong  solution  of  sumac. 

The  method  of  filling  the  bags  with  the  stronger 
solution  is  as  follows,  and  is  performed  by  two  men  and  a 
boy.  Taking  their  places  by  the  side  of  the  smaller  tub, 
the  lad  takes  one  of  the  bags  and  inserts  the  neck  of  a 
funnel  in  its  opening,  when  one  of  the  workmen  nearly 
fills  the  bag  through  the  funnel  with  the  strong  sumac 
solution  by  means  of  a  ladle  (Fig.  50).  The  second  man 
then  takes  the  bag  from  the  funnel  and  inflates  it  with 
his  breath,  after  which  he  closes  the  aperture  by  tying  it 


286 


LEATHER  MANUFACTURE. 


with  a  piece  of  string.  The  bag,  in  its  distended  condition, 
is  perfectly  free  from  wrinkles,  the  presence  of  which 
would  interfere  with  the  uniform  action  of  the  tanning 
material,  and  its  contained  air  enables  the  bag  to  float  in 
the  liquor  of  the  larger  vessel.  All  the  bags,  as  they 
are  filled,  are  thrown  into  this  larger  tub,  in  which  they 
float  like  bladders,  and  they  are  kept  in  constant  motion 
for  about  three  hours  in  this  way :  two  men,  one  on  each 


Fig.  50. 

side  of  the  tub,  take  each  a  wooden  paddle,  which  they 
work  to  and  fro  in  the  solution,  causing  the  floating  bags 
to  roll  gently  over  and  over,  by  which  the  sumac  solution 
in  the  bags  becomes  uniformly  diffused  over  their  inner 
surface,  and  eventually  permeates  the  entire  substance  of 
the  skin  ;  the  absorption  of  the  tanning  principle  is  greatly 
aided  by  the  warm  temperature  of  the  solution  in  which 
the  skins  are  floated.  The  goat  skins  being  very  thin,  are 
effectually  tanned  by  this  method  in  a  few  hours.  In 
Fig.  50  a  workman  is  also  seen  in  the  act  of  moving  the 
floating  bags  about  in  the  sumac  tub.  During  the 
process  of  sumaching  the  bags  are  removed  once  from 
the  tub,  and  are  piled  up  in  a  heap  upon  a  rack  near 
the  tub,  and  by  means  of  their  own  weight  the  sumac 
solution  is  forced  through  the  pores  of  the  skins.  After 


LIGHT  LEATHERS.  287 

this  they  are  subjected  to  another  sumaching  operation, 
and  are  then  once  more  piled  up  in  a  heap  to  acquire 
the  necessary  pressing,  by  which  time  the  operation  is 
complete. 

The  bags  are  now  removed  to  another  apartment,  where 
the  stitching  is  undone  and  the  sediment  which  remains 
from  the  sumac  is  removed  from  the  interior.  This  refuse 
generally  consists  partly  of  yellowish  sandy  matter  with 
which  the  material  had  been  adulterated  before  importation 
from  Sicily.  This  waste,  being  of  no  farther  use  in  tan- 
ning, is  sold  as  manure.  The  tanned  pelts  are  next 
thoroughly  washed,  and  are  then  laid  out  smoothly  upon 
a  sloping  board  ;  they  are  next  "  struck,"  as  it  is  termed 
— that  is,  scraped  and  rubbed  until  they  are  perfectly 
smooth.  They  are  then  hung  up  in  a  loft  to  dry.  When 
dried  they  are  said  to  be  in  t/ie  crust,  and  present  a  some- 
what shrivelled  and  irregular  appearance.  To  render 
them  smooth,  preparatory  to  dyeing  them,  the  skins  are 
first  wetted,  and  then  once  more  Struck,  or  smoothed,  as 
before,  after  which  they  are  ready  for  the  dyeing-house. 
The  process  of  dyeing  Morocco  and  other  leathers  is  given 
in  another  chapter. 

Imitation  Morocco  Leather. — This  is  chiefly  prepared 
from  sheep  and  calfskins,  and  is  extensively  used  for  bags, 
bookbinding,  chair-covers,  and  many  other  useful  pur- 
poses, and  as  now  manufactured  bears  a  close  resemblance 
to  the  true  Morocco.  The  sheep  skins,  before  they  come 
into  the  tanner's  possession,  are  deprived  of  their  wool  by 
a  class  of  manufacturers  called  fellmongcrs,  who  receive  the 
skins  in  the  condition  in  which  they  leave  the  slaughter- 
houses. After  the  skins  are  fellmongered,  the  wool  is  dis- 
posed of  to  the  woolstapler,  and  the  fells,  as  they  are 
termed,  to  the  tanner  and  manufacturers  of  parchment. 

The  unwoolled  sheep  skins  or  fells  are  treated  much  in 
the  same  way  as  goat  skins ;  since  the  skin  of  the  sheep, 
however,  is  naturally  of  a  more  greasy  and  oily  nature 
than  that  of  the  goat,  it  requires  very  careful  treatment  to 
remove  these  greasy  matters  before  being  submitted  to  the 
operation  of  sumac  tanning  ;  the  skins  are  therefore  first 


288  LEATHER  MANUFACTURE. 

submitted  to  powerful  hydraulic  pressure,  by  which  the 
greasy  matters  are  forced  out  from  the  pores  of  the  skin. 
They  are  then  subjected  to  the  same  treatment  as  goat 
skins,  excepting  'that  they  are  tanned  by  immersion  in 
sumac  liquor  instead  of  being  sewn  up  into  the  form  of 
bags,  as  in  the  case  of  goat  skins. 

Skiver. — When  sheep  skins  are  split  by  means  of  the 
splitting  machine,  the  grain  splits,  as  they  are  called,  are 
converted  into  a  thin  variety  of  leather  called  skiver,  which 
is  much  used  for  common  bookbinding,  pocket-books,  hat 
linings,  and  other  purposes  requiring  a  cheap  but  strong 
leather.  The  flesh  splits,  as  we  have  before  said,  are  em- 
ployed for  making  inferior  kinds  of  chamois  or  oiled 
leather.  The  thin  skivers,  being  more  readily  acted 
upon  by  the  sumac  tan  than  goat  skins,  are  not  sewn  up 
into  bags,  but  are  immersed  in  the  sumac  tub  in  an  open 
state,  and  are  tanned  in  a  very  short  time. 

Cordovan  Leather. — This  leather  derives  its  name  from 
the  city  of  Cordova,  in  Spain,  where  it  is  supposed  to  have 
been  originally  prepared  by  the  Moors.  It  has  a  very  fine 
and  beautiful  grain,  and  is  dyed  in  every  variety  of  shade 
and  colour.  The  finest  qualities  are  imported  from  the 
Levant,  but  those  of  Spain,  France,  Hungary,  and  Ger- 
many are  also  highly  esteemed.  The  skins  employed  in 
the  manufacture  of  Cordovan  leather  are  those  of  the  goat 
and  dog,  and  sometimes  also  hog  skins  are  used,  but  the 
leather  prepared  from  goat  skins  is  preferred.  The  skins 
after  being  cleaned  and  drenched  in  water,  are  limed,  after 
which  they  are  again  steeped  in  water  for  eight  to  fifteen 
days,  during  which  period  they  are  repeatedly  worked  by 
treading  upon  them  with  the  feet.  At  the  end  of  a  fort- 
night they  are  steeped  in  a  lukewarm  mixture  of  dogs' 
dung  and  water,  next  into  a  bran  bath,  and  after  removal 
from  the  latter,  the  skins  are  then  stretched,  pressed 
between  two  boards,  and  rubbed  with  common  salt.  They 
are  next  immersed  in  a  bath  prepared  from  figs  and  water. 
Only  skins  that  are  to  be  coloured  black  are  dyed  after 
being  tanned.  Black  leather  is  tanned  in  liquor  of  extract 
of  oak-bark  ;  that  of  lighter  colour  in  ooze  prepared  from 


LIGHT  LEATHERS.  289 

extracts  of  sumac  and  nut-galls.  When  the  operation 
of  tanning  is  complete  the  leather  is  withdrawn,  taking 
with  it  as  little  liquor  as  possible,  and  spread  in  the 
shade,  when  it  must  be  rubbed  on  the  bloom  with  oil  of 
sesame  before  the  sides  have  become  perfectly  dry. 
After  the  oil  is  laid  on,  drying  in  the  shade  is  allowed 
to  be  completed,  when  the  skins  are  folded  on  the  flesh 
side.  When  it  is  desired  to  give  the  Cordovan  a  rough 
appearance,  the  surface  may  be  rubbed  with  a  blunt  knife 
immediately  after  spreading.  In  many  parts  of  Russia 
wormwood  (Artemisia  absinthium)  is  employed  to  fix  the 
colour  in  the  leather.  If,  for  example,  it  is  desired  to  dye 
the  leather  black,  a  decoction  of  wormwood  is  mixed  with 
powdered  cochineal,  and  alum  is  then  added. 

In  the  island  of  Cyprus,  Cordovans  are  dyed  red  in  the 
following  manner : — The  skins,  generally  about  fifty  at  a 
time,  are  placed  in  a  fig  bath ;  they  are  then  passed  into 
a  strong  solution  of  alum  heated  to  about  the  temperature 
of  new  milk ;  they  are  afterwards  hung  upon  poles  to  drain, 
and  are  next  stretched  to  expel  as  much  moisture  as  pos- 
sible ;  finally,  the  skins  are  placed  on  a  table,  and  after 
being  uniformly  stretched,  the  red  colour  is  applied  with  a 
cotton  rag.  The  colouring-matter  is  prepared  by  taking 
ground  cochineal  and  boiling  it  in  soft  water  in  a  well- 
tinned  kettle,  and  during  the  ebullition  5  ozs.  of  powdered 
alum  are  added  for  every  5  ozs.  of  cochineal,  and  the  liquor 
boils  until  reduced  to  one-sixth  or  one-eighth  by  evapora- 
tion, when  it  is  passed  through  a  filter.  The  skins  are 
coated  four  or  five  times  with  this  preparation,  and  after 
being  placed  in  the  tanning  liquor  are  submitted  to  the 
operations  of  dressing. 

In  Hungary  and  Transylvania,  where  the  manufacturers 
of  Cordovan  produce  goods  which  are  highly  esteemed,  the 
red  colour  is  laid  on  in  a  different  manner.  When  the  skins 
have  been  properly  prepared,  they  are  fastened  together  in 
pairs,  in  the  form  of  bags,  with  the  sides  to  be  coloured 
inside.  Into  an  opening  in  this  bag  the  warm  colouring- 
matter  is  poured,  and  in  order  to  insure  uniformity  of  its 
action  the  bag  is  occasionally  agitated  by  being  rolled  about. 

U 


290  LEATHER  MANUFACTURE. 

Roan. — This  leather  is  prepared  from  sheep  skins,  much 
in  the  same  way  as  Morocco,  being  tanned  with  sumac, 
but  in  the  after  processes  of  currying  it  is  not  grained  like 
the  latter. 

Hungary  Leather. — The  mode  of  preparing  this  leather, 
which  is  peculiar,  consists  in  impregnating  strong  hides 
with  alum,  common  salt,  and  tallow,  by  a  quick  process, 
which  is  generally  complete  in  about  two  months.  The 
process  is  thus  given  by  Ure : — "  The  workshop  is  divided 
into  two  parts.  1.  A  shed  on  the  side  of  a  stream,  fur- 
nished with  wooden  horses,  fleshing-knives,  and  other 
small  tools.  In  one  corner  is  a  furnace  with  a  boiler  for 
dissolving  the  alum,  a  vat  for  immersing  the  hides  in  the 
solution,  and  several  tubs.  2.  A  chamber  6  feet  high  by 
15  feet  square,  capable  of  being  made  very  tight  for  pre- 
serving the  heat.  In  one  corner  is  a  copper  boiler,  of 
sufficient  size  to  contain  170  Ibs.  of  tallow.  In  the  middle 
of  the  stove  is  a  square  stone  slab,  upon  which  an  iron 
grate  is  placed  about  a  yard  square.  This  is  covered  with 
charcoal.  At  each  side  of  the  stove  are  large  tables,  which 
occupy  its  whole  length,  and  on  which  the  leather  is  spread 
to  receive  the  grease.  The  upper  part  below  the  ceiling  is 
filled  with  poles  for  hanging  the  leather  upon  to  be  heated. 
The  door  is  made  to  shut  perfectly  close.  The  first  opera- 
tions are  analogous  to  those  of  tanning  and  tawing,  the 
skins  being  washed,  cut  in  halves,  shaved,  and  steeped  for 
twenty-four  hours  in  the  river.  They  are  cleaned  with 
5  or  6  Ibs.  of  alum  and  3 \  Ibs.  of  salt  for  a  piece  of  hide 
which  weighs  70  to  80  Ibs.  The  common  salt  softens  the 
effect  of  the  alum,  attracts  moisture  from  the  air,  and  pre- 
serves the  suppleness  of  the  skin.  When  the  alum  and  salt 
are  dissolved,  hot  water  is  poured  upon  the  hides  placed  in 
a  vat,  and  they  are  trampled  upon  by  a  workman  walking 
repeatedly  from  one  end  of  the  vat  to  the  other.  They 
are  then  transferred  into  a  similar  vat  containing  hot 
water,  and  similarly  trampled  upon.  They  are  next  steeped 
for  eight  days  in  alum-water.  The  same  round  of  opera- 
tions is  repeated  a  second  time. 


LIGHT  LEATHERS.  291 

"  The  skins  are  now  dried  either  in  the  air  or  a  stove- 
room,  but  before  being  quite  dry  they  are  doubled  together, 
well  stretched  to  take  out  the  wrinkles,  and  piled  up.  When 
dry  they  are  again  trampled  to  open  the  pores,  as  well  as  to 
render  the  skins  pliant,  after  which  they  are  whitened  by 
exposure  to  the  sun.  Tallow  of  inferior  quality  is  employed 
for  greasing  the  leather.  With  this  view  the  piece  is 
hung  upon  the  poles  in  the  close  stove-room,  then  laid 
upon  the  table  and  besmeared  with  the  tallow  melted  till 
it  begins  to  crumble.  This  piece  is  laid  on  another  table,  is 
there  covered  with  a  second  similarly  greased,  and  so  forth. 
Three  pounds  of  fat  are  commonly  employed  for  one  piece 
of  leather.  When  the  thirty  strips,  or  tif  teen  hides,  passed 
through  the  grease  in  one  operation  are  completed,  two 
workmen  take  the  first  piece  in  their  hands,  and  stretch  it 
over  the  burning  charcoal  on  the  grate  for  a  minute,  with 
the  flesh  side  to  the  fire.  The  rest  are  passed  over  the 
flame  in  like  manner.  After  flaming,  the  pieces  are  suc- 
cessively laid  on  an  inclined  table  exposed  to  the  fire, 
where  they  are  covered  with  a  cloth.  They  are  finally 
slung  upon  poles  in  the  air  to  dry ;  if  the  weather  be 
warm,  they  are  suspended  only  during  the  night,  so  as 
to  favour  the  hardening  of  the  grease.  Instead  of  the 
alum  bath,  M.  Curaudau  has  employed  with  advantage  a 
steep  of  dilute  sulphuric  acid." 

Wallachia 'Leather. — The  following  is  an  abridgment 
of  Morfit's  description  of  the  Wallachian  method.  This 
leather  is  prepared  by  barley  dressings  in  a  simple  warm 
vat,  and  the  skins  are  unhaired  by  a  fermentative  process 
instead  of  the  usual  liming.  Dry  hides,  after  being 
softened  in  water,  are  first  trampled  upon  and  then 
worked  on  the  flesh  side  upon  the  beam,  to  render  them 
pliant ;  they  are  next  steeped  in  water  for  a  short  time, 
and  then  hung  up  to  drain.  They  are  now  examined,  to 
ascertain  if  the  hair  comes  away  easily ;  for  in  hot  climates 
during  the  summer-time  this  is  effected  without  any  other 
process  of  depilation.  When  fresh  skins  are  employed, 
fermentation  is  resorted  to  for  loosening  the  hair.  After 


292  LEATHER  MANUFACTURE. 

removing  tlie  tail,  horns,  and  ears,  the  skins  are  salted 
without  being  soaked.  The  salting  consists  in  sprinkling 
each  large  hide  with  four  to  six  pounds  of  salt,  alum,  and 
saltpetre  ;  the  hides  are  then  folded  and  stacked  in  a  heap, 
which  is  then  covered  with  litter.  After  a  short  time  the 
hides  become  heated,  and  they  are  turned  over  once  or 
twice  a  day,  so  as  to  render  the  fermentative  process  uniform 
throughout.  When  it  is  found  that  the  hair  yields  to  the 
touch,  the  operation  of  unhairing  is  promptly  performed, 
since  if  the  skins  were  allowed  to  remain  for  too  long  a 
period  under  the  influence  of  the  fermenting  process,  the 
pelt  would  suffer  decomposition  and  consequent  injury. 
In  cases  where  it  is  inconvenient  to  unhair  the  skins 
immediately  they  are  in  the  proper  condition,  they  are 
steeped  in  water  for  one  or  two  days,  but  not  longer; 
otherwise  putrefaction  would  ensue. 

Raising. — When  the  depilation  is  effected,  the  pelts  are 
treated  in  a  bath  composed  as  follows : — For  seven  skins, 
each  averaging  80  Ibs.,  20  Ibs.  of  flour  are  made  into  leaven, 
which  is  worked  up  into  a  pasty  condition  with  water  ;  to 
this  a  gill  and  a  half  of  vinegar  is  added  to  promote  the 
acetous  fermentation.  The  preparation  of  the  leaven 
occupies  about  twenty-four  hours,  and  the  vessel  in  which 
it  is  placed  must  be  kept  in  a  warm  place,  well  covered 
up  for  three  or  four  days.  The  tub  for  seven  skins  is 
about  five  and  a  quarter  feet  across,  and  three  and  a  quarter 
feet  high,  and  must  be  perfectly  clean  and  free  from  any 
matter  which  would  check  the  progress  of  the  fermenta- 
tion. The  tub  is  filled  with  water,  with  which  the  leaven 
is  well  incorporated  by  stirring.  Six  or  seven  bucket- 
fuls  of  the  liquor  are  then  put  into  a  kettle  and  boiled,  and 
a  portion  of  this  used  to  make  a  uniform  paste  with  ground 
barley,  and  this  is  afterwards  thinned  with  cold  water 
until  it  has  a  syrupy  consistence.  This  compound  is  next 
boiled  until  it  froths,  and  is  kept  constantly  stirred  with  a 
wooden  paddle.  When  the  compound  has  frothed  up 
three  times,  it  is  ladled  into  the  tub  to  be  employed  for 
the  dressing,  and  cooled  down  by  stirring  continually  in 
one  direction,  until  the  hand  can  readily  bear  its  tern- 


LIGHT  LEATHERS.  293 

perature.  Six  pounds  of  salt  are  then  added  and  well 
stirred  in,  and  the  tub  is  then  covered  up  and  allowed 
to  repose  for  a  fortnight  to  sour,  the  mixture  being 
stirred  twice  a  day  during  this  time,  and  the  vessel  being 
immediately  covered  after  each  stirring. 

The  skins  being  removed  from  the  rinsing  water,  are 
strung  in  threes  with  a  cord  and  thrown  into  the  tub, 
where  they  are  allowed  to  remain  for  four  or  five  days, 
being,  however,  drawn  twice  daily  and  left  to  drain  for  a 
minute,  and  then  returned  to  the  tub.  When  the  skins 
are  sufficiently  soft,  they  are  next  fleshed  and  unhaired, 
and  are  then  rinsed  in  clean  water,  after  which  they  are 
hung  up  to  drain  for  twenty-four  hours.  While  the  above 
operations  are  in  progress,  a  second  leaven  is  prepared 
from  16  Ibs.  of  meal,  and  fermented  in  the  same 
way  as  the  former.  The  clear  sour  liquor  of  the  first 
dressing  is  now  transferred  to  a  second  tub,  in  which  the 
dressing  is  completed.  Six  or  seven  bucketfuls  of  the 
clear  sour  liquor  are  taken  from  each  tub,  and  a  portion 
stirred  up  with  50  Ibs.  of  ground  barley — about  8  Ibs.  for 
each  skin.  The  remaining  hot  water  is  then  added 
gradually,  and  the  whole  gently  boiled  and  added  to  the 
new  dressings  and  well  stirred  in.  One  or  two  bucket- 
fuls are  taken  out  and  heated  to  near  the  boiling-point. 
Another  leaven,  prepared  from  8  Ibs.  of  meal,  is  then 
diffused  through  the  tubs,  and  from  4  to  6  Ibs.  of  salt 
added  to  each,  with  stirring.  The  process  may  be  sim- 
plified by  making  one  steep  instead  of  two,  by  using  at 
first  30  Ibs.  of  leaven,  120  Ibs.  of  barley,  and  10  Ibs.  of 
salt  for  each  dressing  of  six  hides. 

Relative  to  barley  dressing,  Morfit  says,  "It  must  be 
observed  that,  by  the  ordinary  process,  the  tanners  use  at 
one  time,  in  their  first  new  dressings,  just  twice  the 
quantity  of  barley  that  would  be  employed  here  [Wai- 
lachia],  and,  moreover,  when  their  first  new  dressing  is 
not  sufficient,  they  are  obliged  to  make  a  second,  which 
renders  the  process  more  tedious  and  expensive  than  that 
of  Wallachia.  It  is  also  necessary  to  say  that,  on  the 
addition  of  salt,  the  dressing  must  always  be  well  stirred, 

/"^ 


294  LEATHER  MANUFACTURE. 

and  two  or  three  bucketfuls  of  the  liquor  drawn  out  from 
each  and  kept  warm,  to  be  poured  into  the  vat  in  order 
to  maintain  the  temperature.  Several  other  bucketfuls  are 
also  taken  out  and  poured  into  a  reserve  tub,  so  that  no 
more  liquor  may  remain  in  each  dressing  than  is  sufficient 
to  cover  the  skins  subjected  to  its  action.  Many  tanners 
believe  that  it  is  better  to  make  the  whole  composition 
at  once,  for  independently  of  loss  of  time  and  fuel,  the 
complement  made  with  the  new  quantity  of  barley  may 
retard  the  progress  of  fermentation,  and  the  liquor  must 
be  heated  to  a  temperature  which  would  be  injurious  to 
the  skins." 

There  are  several  methods  of  preparing,  the  composition 
for  barley  dressing :  1,  from  barley  or  rye  meal,  without 
leaven,  prepared  overnight  with  boiling  water ;  2,  from 
equal  parts  of  barleymeal  and  leaven,  thinned  with  water, 
and  heated  to  boiling  just  previous  to  putting  in  the  skins  ; 
3,  from  wheat  bran,  in  the  proportion  of  half  a  bushel  per 
hide,  weakened  with  hot  water,  and  after  a  day's  fermen- 
tation mixed  with  1  Ib.  of  salt  for  each  skin  ;  4,  from 
leaven  of  barley  or  rye,  in  the  proportion  of  from  6  to  8  Ibs. 
of  meal  per  hide.  When  the  leaven  rises,  it  must  be 
thinned  with  water  at  86°  Fahr.,  and  the  salt  added  just 
before  the  skins  are  immersed. 

Barley  Dressing.  —  When  the  fermentation  is  well 
established,  which  is  indicated  by  the  liquor  becoming 
sour,  the  dressings,  as  they  are  called,  are  ready  for  the 
skins,  which  are  taken  from  the  hangers  and  passed 
through  the  liquor  several  times,  so  as  to  equalise  the  tem- 
perature. They  are  now  left  upon  the  cover  of  the  tub  for 
a  few  minutes  to  drain  ;  the  liquor  is  then  stirred,  and 
the  skins  returned  to  the  tubs,  which  are  then  covered, 
and  the  temperature  of  the  dressings  is  kept  up  by 
additions  of  the  hot  reserve  liquors.  In  a  quarter  of  an 
hour  the  skins  are  again  drawn  out  and  left  to  drain  as 
before,  after  which  they  are  replaced  in  the  tub,  and  half 
an  hour  after  are  again  withdrawn  and  left  to  drain  for 
a  quarter  of  an  hour.  They  are  then  replaced  in  the  tub, 
again  removed,  and  drained  for  twenty  minutes.  In  the 


LIGHT  LEATHERS.  295 

fifth  dipping  the  skins  are  left  in  the  bath  for  an  hour, 
after  which  they  are  drained  for  half  an  hour,  and  then 
returned  to  the  tub.  These  operations  are  repeated  in  all 
about  eight  times.  If,  on  the  following  day,  the  hides  are 
not  sufficiently  raised,  they  are  dipped  several  times  more 
until  the  required  condition  is  attained.  The  heat  of  the 
dressings  must  be  kept  at  from  105°  to  120°  Fahr.  by 
additions  of  hot  liquor. 

Morfit's  Remarks  on  White  Dressing.  — "  Experience 
has  proved  that  the  action  of  the  white  dressing  is  com- 
pleted in  about  thirt}r-six  hours  ;  the  acetic  fermentation 
which  is  established  so  expands  the  hides  that  they  become 
as  thick  as  the  leather  into  which  they  are  about  to  be  con- 
verted. Care  must  be  taken  not  to  leave  them  any  longer 
in  the  liquor  after  this  point  has  been  attained,  for  it  in- 
jures the  leather,  a  result  which  also  takes  place  if  the 
liquor  is  too  strong.  After  the  removal  of  the  skins  from 
the  liquor,  the  latter  must  be  reserved  for  new  dressing, 
for  which  purpose  it  must  be  heated  with  a  complement 
somewhat  stronger  than  the  first.  This  acid  liquor  greatly 
facilitates  the  fermentation  of  the  new  composition,  which 
sours  rapidly.  In  this  manner,  when  the  white  dressings 
are  once  in  train,  they  may  be  kept  at  one-half  the  expense 
of  flour,  time,  and  money." 

When  removed  from  the  dressings,  the  hides  are  left  to 
drain  on  the  cover,  and  when  cooled  are  soaked  in  water 
for  a  few  moments  to  remove  the  viscid  coating  derived 
from  the  barley,  and  they  are  then  again  drained. 

Red  Dressing. — The  skins  are  now  subjected  to  what 
is  termed  the  red  dressing,  preparatory  to  their  being 
placed  in  the  tan-vats.  This  dressing  is  made  by  putting 
about  40  Ibs.  of  crushed  bark,  mixed  with  water,  into  a 
tub.  Into  this  the  hides  are  then  placed,  and  allowed 
to  remain  for  several  hours,  when  they  are  taken  out  and 
drained  for  a  few  minutes.  A  few  hours  after  further 
immersion  this  operation  is  repeated,  but  previous  to 
returning  the  skins  to  the  vat  the  last  time  an  addition 
of  40  Ibs.  more  crushed  bark  is  made,  and  this  is  well 
stirred  in.  On  the  mornings  of  the  second  and  third 


296  LEATHER  MANUFACTURE. 

days,  24  Ibs.  of  bark  are  added,  the  skins  taken  out 
thrice  daily,  half  an  hour  being  allowed  for  each  drain- 
ing. On  the  fourth  day  the  skins  are  drained  morning 
and  evening,  forty-five  minutes  being  allowed  each  time. 
On  the  morning  of  the  fifth  day  the  hides  are  taken  out, 
and  while  draining  the  liquor  is  well  stirred.  The  hides 
are  then  put  back,  hair  side  upward,  and  a  few  handfuls 
of  crushed  bark  thrown  in  between  each  skin,  and  on  the 
top  of  the  last  one,  which  should  have  its  flesh  side  upward, 
a  layer  of  bark  is  spread.  The  skins  are  now  left  for  eight 
to  ten  days,  then  removed,  rinsed  in  clean  water,  and  put 
into  the  tan- vats. 

Bran  Dressing. — Some  tanners  contend  that  the  red 
dressings  may  be  omitted  if  the  white  dressings  are  made 
with  bran.  The  unanimous  opinion  of  many  tanners 
whom  we  have  consulted  on  the  subject  is  in  favour  of  red 
dressings.  The  bran  dressings  are  prepared  either  hot  or 
cold.  In  the  first,  the  leaven  is  prepared  from  yeast,  or 
made  with  1  to  1  \  Ibs.  of  wheat  or  rye  flour  per  hide,  and 
kept  at  a  moderate  temperature,  which  quickly  sours. 
After  the  skins  have  been  soaked  and  cleansed,  they  are 
lleshed  and  rinsed  in  water.  They  are  then  put  into  a 
bath  composed  of  bran  liquor  as  follows  :  A  sufficient 
quantity  of  water  for  all  the  skins  is  boiled  with  bran,  in 
the  proportion  of  7  or  8  Ibs.  for  each  skin ;  the  boiler 
is  then  covered,  and  when  the  liquor  has  sufficiently  fer- 
mented, which  is  known  by  the  bran  rising  to  the  sur- 
face, the  liquor  is  transferred  to  a  vat  in  which  the  skins 
were  previously  deposited.  While  the  skins  are  getting 
warmed,  another  quantity  of  water  is  heated  until  it  sim- 
mers, when  to  this  is  added  the  fermented  liquor  first  pre- 
pared. The  skins  are  then  taken  out  of  the  vat,  and  the 
fresh  mixture  is  poured  in,  with  the  addition  of  salt  in  the 
proportion  of  rather  more  than  1  Ib.  per  skin,  and  the 
whole  is  well  stirred.  The  skins  are  now  placed  in  the 
vat,  where  they  are  allowed  to  remain  for  about  six  hours. 
They  are  then  removed  and  drained  for  a  short  time,  and  a 
portion  of  reheated  liquor  put  into  the  vat.  The  same 
operations  are  repeated  every  six  hours  during  two  days. 


LIGHT  LEATHERS.  297 

When  the  hair  is  loosened  it  is  removed  in  the  usual  way, 
after  which  the  skins  are  fleshed  and  soaked  in  cold  water 
for  a  quarter  of  an  hour ;  they  are  then  returned  to  the 
vat,  and  allowed  to  remain  until  sufficiently  raised.  By 
reheating  a  portion  of  the  liquor  from  time  to  time,  and 
keeping  the  vessel  covered,  the  raising  will  generally  be 
effected  by  the  end  of  three  days.  The  skins  are  now 
rinsed  and  left  in  soak  for  some  hours  in  fresh  water,  when 
they  are  ready  for  the  subsequent  tanning  operations. — 
Morfit. 

Enamelled  Leather. — This  variety  of  leather,  which 
for  a  long  period  was  known  under  the  title  of  "patent 
leather,"  is  prepared  from  calf,  seal,  and  other  skins,  with 
a  varnish  composed  of  drying  oil,  vegetable  black,  and 
Prussian  blue.  The  skin  is  first  stretched  on  a  flat  board, 
and  every  trace  of  grease  is  then  removed  from  the  surface 
by  means  of  a  paste  made  with  fuller's  earth  and  water, 
which  is  afterwards  thoroughly  removed  by  rubbing. 
The  skin  is  then  ready  to  receive  the  first  coat  of  varnish, 
which  is  composed  of  Prussian  blue  (that  which  contains 
some  alumina)  5  ounces ;  drying  oil,  1  gallon.  These 
being  well  mixed  or  ground  together,  are  boiled  to  the 
consistence  of  "single  size;"  and  when  cold,  a  small 
quantity  of  vegetable  black  is  added  and  ground  up  with 
the  mixture.  The  first  coat  is  given  by  pouring  some  of 
the  varnish  over  the  leather,  and  then  spreading  it  over 
thinly  with  a  kind  of  scraper  until  the  entire  surface  is 
evenly  coated.  The  leather  is  then  placed  in  a  drying 
stove,  and  when  sufficiently  set  is  placed  aside  to  cool ;  it 
is  afterwards  polished  with  finely-powdered  pumice.  A 
second  coating  is  then  given  with  the  varnish,  in  which  a 
little  pure  Prussian  blue  has  previously  been  mixed,  and 
the  leather  is  again  stoved  and  polished  with  pumice  as 
before.  For  the  third  coat  the  varnish  consists  of  a  similar 
mixture,  but  the  oil  is  boiled  until  it  strings  well,  and  a 
little  more  Prussian  blue  and  vegetable  black  are  added, 
the  varnishing,  stoving,  and  polishing  being  pursued  as 
before.  The  last  coat,  or  finish,  is  given  with  a  varnish 
like  the  third,  with  the  addition  of  £  lb.  of  pure  dark- 


298  LEATHER  MANUFACTURE. 

coloured  Prussian  blue  and  J  Ib.  of  pure  vegetable  black 
per  gallon,  and  to  this  a  little  oil,  copal,  or  amber  varnish 
are  sometimes  added.  The  heat  of  the  stove  or  oven  is 
usually  about  120°  Fahr.  for  enamelled  skins,  as  those  of 
calf  and  seal  intended  for  uppers,  and  175°  Fahr.  to  180° 
Fahr.  for  stout  "  Japan  leather."  The  exposure  in  the 
stove  is  commonly  from  six  to  ten  hours. 


CHAPTER  XXV. 
DYEING  LEATHER. 

Dyeing  Morocco  Leather.— Dyeing  with  Aniline  Colours. — Dyeing  Kid 
Leather  for  Boots.— Bath  Dyeing. — Dyeing  on  a  Flat  Surface. — 
Aniline  Colours  in  Glove  Dyeing.— Dyeing  with  Pure  Aniline 
Colours. 

Dyeing  Morocco  Leather. — After  the  goat  skins  have 
been  snrnached,  opened,  and  well  washed,  they  are  spread 
out  upon  a  sloping  board  and  struck  out,  that  is  scraped  and 
rubbed  out  as  smooth  as  possible,  after  which  they  are 
hung  up  in  the  loft  to  dry.  When  thoroughly  dried  they 
are  in  a  hard  and  shrivelled  condition,  and  are  said  to  be 
"  in  the  crust."  To  bring  the  skins  to  a  proper  condition 
to  receive  the  dye,  they  are  tirst  softened  or  "  seasoned  " 
in  water,  after  which  they  are  struck  out  or  smoothed 
again,  when  they  are  ready  for  dyeing.  Since  Morocco 
leather  only  requires  to  be  coloured  or  dyed  on  one  side, 
it  is  usual  to  lay  two  skins  of  the  same  size  in  close  con- 
tact, flesh  to  flesh,  before  dyeing,  so  that  the  dye  liquor 
may  only  penetrate  one  side  of  each  skin.  For  red  Mo- 
rocco, the  skins  are  first  mordanted  either  with  a  solu- 
tion of  tin  or  with  alum  water,  after  which  they  are 
immersed  in  a  bath  prepared  from  cochineal,  boiled  in 
water,  with  a  little  alum  or  tartar  added,  the  liquor 
being  filtered  through  a  linen  cloth  before  use.  After 
about  half  an  hour  the  skins  are  withdrawn  and  then 
subjected  to  another  immersion  in  the  cochineal  bath. 
They  are  then  rinsed,  drained,  oiled  on  the  grain  side, 
and  hung  up  to  dry,  after  which  they  are  transferred  to 
the  currier. 


3oo  LEATHER  MANUFACTURE. 

Black  Dye  is  given  by  brushing  over  the  grain  side  a 
red  solution  of  acetate  of  iron.  For  blue,  the  cold  indigo 
vat  is  used.  Violet  is  produced  by  first  dyeing  a  pale  blue, 
and  afterwards  dipping  in  the  red  cochineal  vat.  For  green, 
Saxon  blue,  followed  by  a  yellow  dye,  produced  by  the 
chopped  roots  of  barberry.  Puce  colour  is  produced  by 
logwood,  with  a  little  alum  added  ;  olive,  by  first  passing 
the  skins  through  a  weak  solution  of  copperas,  and  next 
through  the  decoction  of  barberry  root  containing  a  little 
Saxon  blue.  After  dyeing,  the  skins  are  rinsed  and 
drained,  after  which  they  are  laid  flat  on  a  table,  and 
smeared  over  with  linseed  oil  on  the  grain  side  by  means 
of  a  sponge,  to  render  the  surface  glossy  when  curried,  and 
also  to  prevent  them  from  drying  too  rapidly  and  thus  be- 
coming hard  and  flinty. 

Dyeing  with  Aniline  Colours. — Since  the  introduction 
of  the  famous  aniline  or  coal-tar  dyes,  many  hues  have 
been  given  to  leathers  which  could  not  be  produced  with 
equal  facility  by  means  of  the  ordinary  dye  stuffs.  The 
great  brilliancy  of  the  aniline  dyes,  and  the  readiness  with 
which  they  combine  with  animal  substances,  render  them 
most  potent  auxiliaries  in  the  dyeing-room,  and  with  ne- 
cessary care  in  their  employment  they  are  capable  of  pro- 
ducing a  great  variety  of  tones  or  shades  of  exquisite 
brilliancjr. 

The  Gerber  Zeitung,  to  which  the  leather  trades  are  in- 
debted for  much  valuable  information,  has  recently  contri- 
buted a  series  of  memoirs  upon  dyeing  leather  with  aniline 
colours,  which  cannot  fail  to  prove  highly  serviceable  to 
those  who  are  engaged  in  this  important  branch  of  manu- 
facture. These  papers  having  been  reproduced  in  the 
Dyer  and  Calico  Printer,*  we  are  indebted  to  that  useful 
journal  for  the  following  extracts : — 

Dyeing  Kid  Leather  for  Boots. — The  subject  is  con- 
sidered in  two  main  divisions,  namely,  the  dyeing  of 
leather  for  boots  and  for  gloves.  The  leather  used  for  the 
first-named  purpose  is  usually  that  which  is  too  imperfect 
for  the  manufacture  of  gloves.  The  first  process  is  soften- 
*  The  Dyer  and  Calico  Printer,  February,  March,  and  June,  1884. 


DYEING  LEATHER.  301 

ing  the  skins  in  water.  The  dyeing  is  effected  by  two 
methods — plunging,  or  dyeing  on  the  flat  surface.  In  the 
latter  case  the  skin  is  white  on  the  flesh  side.  In  the  old 
process  of  dyeing  with  wood  colours,  it  was  considered 
necessary  to  adopt  the  plunging  method  for  all  delicate 
shades,  but  with  aniline  colours  this  is  not  necessary. 
With  any  dilute  dye-wood  decoctions  it  is  impossible  to 
produce  on  the  skin  by  means  of  brushing  a  full  and  uni- 
form tone  of  colour,  but  with  aniline  colours  it  is  quite 
possible  to  produce  on  a  flat  surface  the  most  delicate 
shades  obtainable  by  plunging.  The  skins  must  be 
stretched  out  on  a  flat  surface  to  free  them  as  much  as 
possible  from  moisture. 

As  mordants  for  the  so-called  kid  leather  dyeing  the 
following  acids  are  used :  sulphuric,  phosphoric,  tartaric, 
oxalic,  tannic,  and  acetic  acids.  Amongst  the  alkalies 
used  as  mordants  are  soda,  potash,  and  ammonia.  Acids 
must  be  used  with  all  blue  aniline  colours,  with  most 
greens,  as  well  as  with  many  yellows  and  browns.  Alka- 
lies are  used  with  all  red  aniline  dyes  and  with  kindred 
shades. 

Bath  Dyeing. — The  modes  of  dyeing  are,  as  we  have 
said,  bath  dyeing  and  dyeing  on  a  flat  surface.  The  first 
is  carried  out  by  filtering  a  solution  of  the  aniline  colour 
made  with  hot  water.  A  portion  of  this  solution  (of  5  to 
10  per  cent,  strength)  is  poured  into  lukewarm  water  in  a 
vat,  and  the  skins  are  placed  singly  in  it,  a  workman  tread- 
ing them  down  with  his  feet  and  keeping  them  in  motion. 
When  the  colour  has  been  taken  up  by  the  skins,  they  are 
removed  and  subjected  to  slight  pressure,  and  more  colour- 
ing matter  added  to  the  bath,  the  process  being  repeated 
till  the  skins  have  taken  the  desired  shade.  To  determine 
what  the  colour  of  any  particular  stage  will  be  when 
dried,  a  small  piece  is  cut  from  a  corner  and  put  in  a  linen 
cloth  which  is  repeatedly  wrung,  when  the  ultimate  shade 
after  drying  and  dressing  will  be  seen  with  relative  ac- 
curacy. The  skins  are  now  taken  out  and  slightly  pressed, 
the  colouring  liquor  is  poured  off,  except  a  small  residue, 
to  which  yolka  of  eggs  and  salt  are  added  ;  the  skins  are 


302  LEATHER  MANUFACTURE. 

then  replaced  and  the  previous  treatment  renewed.  As 
this  process  gives  a  slightly  yellowish  tinge,  this  fact 
should  be  kept  in  view  in  dyeing  the  shade  in  the  first 
instance.  The  skins  are  then  spread  out  and  allowed  to 
drain,  after  which  they  are  dried. 

To  arrive  at  the  desired  shades,  such  as  pink,  eosine  is 
taken  for  a  yellowish  tinge.  1.  For  pure  pink,  eosine 
two  parts,  phloxine  one  part.  Pink  with  a  bluish  tinge, 
phloxine  two  parts,  eosine  one  part.  Phloxine  for  a  dis- 
tinctly bluish  tinge  in  a  delicate  shade.  2.  Straw  is  pro- 
duced by  the  use  of  naphtholine  yellow,  and  for  specially 
strong  shades  some  methanil  yellow.  3.  For  cream,  a 
very  weak  solution  of  naphtholine  yellow.  4.  Salmon  is 
produced  by  mixing  the  latter  colour  and  eosine  in  the 
following  proportions :  For  the  more  reddish  shades, 
eosine  two  parts,  naphtholine  yellow  one  part ;  for  more 
yellowish  shades,  eosine  one  part,  naphtholine  yellow  one 
part.  Buff,  eosine  and  methanil  yellow  in  equal  propor- 
tions for  the  more  reddish  shades,  and  equal  parts  of 
phloxine  and  methanil  yellow  for  a  bluish  tinge.  For  the 
above  colours  it  is  recommended  to  add  some  phos- 
phate of  soda  to  the  dyeing-bath,  to  facilitate  the  process 
and  impart  brilliancy  to  the  colours. 

Dyeing  on  a  Plat  Surface  is  effected  by  first  applying 
to  the  stretched- out  skin  a  mordant  with  a  medium  soft 
brush.  The  colouring  substance  is  then  applied  with  a 
brush.  After  two  applications  the  skin  is  drained  so  as 
to  allow  fresh  colouring  matter  to  be  taken  up.  When 
the  skin  is  sufficiently  dyed  the  excess  of  colour  is 
removed  with  water.  Draining  then  follows,  and  the 
skin  is  hung  up  to  dry. 

The  following  are  some  of  the  shades  obtained  by  this 
method  : — 1.  Cream  :  Solution  of  naphtholine  yellow  in 
water  one-sixteenth  per  cent.  The  skin  is  mordanted  with  a 
solution  of  phosphate  of  soda  in  water  (proportion  1 :  100). 
Three  brushes  of  the  above  weak  solution  of  dye  stuff  are 
applied,  the  skin  being  drained  after  the  second  brushing. 
As  a  coating,  a  solution  of  dextrine  in  water  mixed  with 
phosphate  of  soda  may  be  used :  phosphate  of  soda  one 


DYEING  LEATHER.  3°3 

part,  dextrine  two  parts,  water  100.  This  coating  can  be 
used  as  a  mordant,  and  produces  a  silky  brilliancy  which 
protects  the  colour  from  the  influence  of  the  air  ;  otherwise 
aniline  colours  fade,  even  without  the  action  of  light.  2. 
Straw  :  Naphtholine  yellow  one  part,  water  4CO  parts. 
Treat  as  before.  3.  Golden  yellow :  Methanil  yellow  one 
part,  water  100  parts.  4.  Pink,  with  yellouisk  tinye  :  A 
solution  of  cosine  made  with  one-sixteenth  per  cent,  of 
eosine.  5.  Pink,  uith  bluish  tinge  :  A  solution  of  phloxine 
(one-sixteenth  per  cent.).  6.  Pure  pink:  A  mixture  of 
the  above  solutions  in  equal  proportions.  7.  Cerise  is  ob- 
tained with  a  one  per  cent,  solution  of  erythrosine,  three 
or  four  brushes  being  used  in  the  subsequent  process.  8. 
Sky  blue  is  obtained  by  means  of  water-blue  D.N.  in 
a  half  per  cent,  solution.  As  a  mordant,  phosphate  of 
soda  in  one  per  cent,  solution,  to  which  tartaric  acid  is 
added  in  the  proportion  of  -J  oz.  to  -J-  oz.  for  22  gallons. 
The  following  mordant  is  recommended  for  all  blue 
and  green  aniline  colours :  water  22  gallons,  phosphate 
of  soda  2ith  Ibs.,  dextrine  21th  Ibs.,  tartaric  acid  f  oz. 
to  1  oz.  9.  Imperial  Uue  (cornflower  blue)  is  ob- 
tained with  water -blue  D.N.  in  a  one  per  cent, 
solution,  the  process  being  as  in  No.  6.  Grey  in  dif- 
ferent shades  is  obtained  by  mordanting  as  1  to  7,  and 
maddering  with  elderberry  juice  or  dogwood-berry  juice 
(two  brushes],  then  as  a  coating  nigrosine  or  indu- 
line  applied  in  a  one  per  cent,  solution.  10.  Green. 
A  light  shade  is  given  with  new  Victoria  green,  and  a 
darker  shade  with  extra  brilliant  green.  11.  Violet:  A 
one  per  cent,  solution  of  methyl  violet  in  water.  When 
the  skins  have  been  dried  they  are  plunged  in  water 
for  a  few  seconds  and  are  then  allowed  to  drain  like 
plates  in  a  rack.  A  glazing  machine  may  then  be  used 
for  finish. 

Aniline  Colours  in  Glove  Dyeing. — While  in  the  so- 
called  kid  leather  used  for  boots  aniline  colours  are  the 
principal  dye  substances  used,  it  is  different  with  glac6 
leather,  in  which  they  are  only  adjuncts.  The  use  of 
aniline  colours  in  dyeing  glove-leather  is  divided  into  the 


304  LEATHER  MANUFACTURE. 

following: — a.  Dyeing  with  pure  aniline  colours.  & 
Maddering  with  pure  dye-wood  or  berry- dye  solutions, 
with  a  coating  of  aniline,  and  with  the  use  of  various 
metallic  salts  for  darkening  or  turning  shades,  c.  The 
mixing  of  different  wood-dyes  as  maddering  substances, 
with  a  coating  of  aniline,  without  employing  any  turning 
substances,  d.  A  pure  or  mixed  decoction  of  dye-wood 
or  berries,  shaded  with  aniline  dyes. 

Dyeing  with.  Pure  Aniline  Colours. — The  process  is 
almost  entirely  confined  to  so-called  plunging  colours, 
used  to  produce  the  most  delicate  shades  for  evening 
wear,  the  processes  b,  c,  and  d  being  carried  out  on  a 
flat  surface.  Phosphate  of  soda,  with  the  addition  of 
a  very  small  quantity  of  tartaric  acid,  may  be  advan- 
tageously used.  The  dyeing  substance  is  added  to  the 
bath  in  very  small  quantities,  by  which  greater  purity 
and  regularity  of  colour  are  obtained.  When  the  de- 
sired tone  has  been  arrived  at,  a  little  dextrine  is  put 
into  the  bath  and  a  little  borax  added.  The  skins  are 
then  well  worked  for  five  minutes  longer,  when  they 
are  taken  out  and  allowed  to  drip,  and  are  afterwards 
pressed.  They  are  then  treated  with  yolk  of  egg  and 
salt,  which  must  be  greater  in  quantity  than  for  kid 
leather.  The  aniline  colours  used  are  naphthol  yellow, 
methanil  yellow,  eosine,  phloxine,  methyl  violet,  nigro- 
sine  W.,  and  induline  ET.N. 

The  following  table  shows  how  the  most  usual  shades 
required  for  opera  and  evening  wear  are  respectively  ob- 
tained by  the  old  and  new  methods : — 

Old  Method.  New  Method. 

Cream  or  Ivory.  .Decoction  of  Persian  berries,  Naphthol  yellow  in  a  very 

•with  a  trace  of  Brazil  wood  dilute  form. 

Straw    Persian  berries Naphthol  yellow. 

Pink Brazil  wood    with   a    little  Two  parts  eosine  with  one 

cochineal  part  phloxine. 

Violet    Alcoholic  extract  of  logwood  Methyl  violet. 

Greenish  Grey  . .  Elderberry  juice,  with  a  little  Nigrosine  W.,  with  a  trace 

carmine  indigo  of  lumiere  green. 

Pearl  Grey    ....Elderberry   juice  and  alco-  Two  parts  nigrosine  W. 

holic  extract  of  logwood  and  one  part  induline 

N.N. 


DYEING  LEATHER.  305 

Old  Method.  New  Method. 

Yellowish  Buff . .  Persian  berries  and  logwood     Four  parts  naphthol  yel- 
low and  one  part  eosine. 

Reddish  Buff. . . .  Persian  berries,  Brazil  wood,    Two    parts    of    methanil 
(Flesh  colour}      and  cochineal  yellow    and    one    part 

phloxine. 

In  mixing  the  above  solutions,  precision  in  quantities 
must  be  observed,  and  it  is  recommended  to  make  solutions 
of  the  strength  of  one-tenth  per  cent.,  in  which  there  is  one 
gramme  (15'43  grains)  of  dye-stuff  to  each  litre  ('22  gallon) 
of  water.  It  is  best  to  make  the  solution  in  a  cold  state  and 
in  bottles  of  moderate  size,  so  that  they  can  be  shaken  to 
prevent  the  particles  of  dye-stuff  from  caking.  After 
pressing,  the  skins  are  placed  in  a  darkened  and  heated 
room  well  ventilated.  The  salts  used  for  toning  down 
colours  are :  copperas  (sulphate  of  iron),  sulphate  of  copper, 
(bluestone),  sulphate  of  zinc,  mixtures  of  copperas  and 
bluestone,  and  potash  alum,  used  in  1  per  cent,  solutions. 
The  reader  is  referred  to  articles  which  appear  from  time 
to  time  in  The  Leather  Trades  Rcvieiv  for  more  elaborate 
details  of  aniline  dyeing  on  leather. 


CHAPTER  XXVI. 
MANUFACTURE  OF   WHITE  LEATHER. 

Tawing  as  distinguished  from  Tanning. — Tawing  Operations. — Kid 
Leather  :  Treatment  of  Kid  Skins. — French  Kid  Leather. — Imita- 
tion Kid. — Continental  Method  of  preparing  Glove  Leather. — Calf 
Kid  for  Uppers.— White  Sheep  Leather.— Splitting  Sheep  Skins. 

Tawing,  as  distinguished  from  Tanning. — In  the  pro- 
cess of  tanning,  as  we  have  seen,  the  gelatine  of  the  skin 
undergoes  a  chemical  change  when  brought  into  contact 
with  tannin,  by  which  tanno-gelatine  is  formed — a  sub- 
stance not  only  insoluble  in  water,  but  which  cannot  be 
again  separated  into  its  two  chief  constituents,  tannic  acid 
and  gelatine,  by  any  known  means.  In  the  process  of 
tawing  t  however,  the  skins  are  subjected  to  the  action  of 
alum  and  salt,  which,  although  they  convert  the  skins  into 
a  substance  resembling  leather  in  some  of  its  attributes, 
cannot  be  said  to  form  a  true  chemical  compound  with  the 
gelatine,  inasmuch  as  the  three  substances — gelatine,  alum, 
and  salt — can  be  again  separated  by  treatment  with  water, 
as  proved  by  the  researches  of  Davy. 

The  arts  of  tanning  and  tawing  are  therefore  perfectly 
distinct,  and  have  no  relation  whatever  to  each  other. 
Some  manufacturers  of  light  leathers,  however,  carry  on 
the  process  of  tanning  calf  and  seal  skins,  as  well  as  the 
tawing  of  goat,  kid,  sheep,  and  other  small  skins. 

Tawing  Operations. — The  chief  operations  of  tawing 
are : — 1.  Soaking,  or  steeping  in  water.  2.  Breaking,  or 
scraping  on  the  flesh  side.  3.  Liming.  4.  Unhairing  and 
fleshing.  5.  Steeping  in  a  Iran-water  drench.  6.  Working 
on  the  learn.  7.  Treatment  with  alum  and  salt.  8.  Egging. 


WHITE  LEATHER.  307 

The  skins  which  are  subjected  to  the  operations  of  tawing, 
or  alum-dressing,  are  those  of  the  kid,  the  calf,  the  lamb, 
and  the  sheep,  the  first  being  employed  to  produce  the 
well-known  hid  leather,  from  which  the  finest  sorts  of 
gloves  and  uppers  of  ladies'  shoes  and  boots  are  made. 
Lamb  skins,  when  prepared  by  the  processes  we  are  about 
to  describe,  form  an  imitation  hid  leather,  from  which  the 
cheaper  kinds  of  "  kid  "  gloves  are  made. 

Kid  Leather  :  Treatment  of  Kid  Skins. — These  skins, 
which  are  chiefly  imported  from  Italy,  are  of  very  small 
size,  and  have  the  hair  on.  For  leather  to  be  employed 
for  the  finest  quality  of  gloves,  the  skins  are  obtained  from 
the  young  goats  before  they  leave  the  mother  to  feed  on 
herbage.  The  imported  skins,  being  in  the  dry  state,  are 
first  subjected  to  the  operation  of — 

Soaking,  or  steeping  in  water,  in  large  tubs  or  vats, 
wherein  they  are  allowed  to  remain  for  about  three  days ; 
at  the  end  of  this  time  the  skins  have  become  considerably 
softened,  when  they  are  next  broken,  as  it  is  termed,  on  the 
flesh  side. 

llreaking. — The  skin  is  laid  upon  the  beam,  flesh  side 
upward,  and  is  then  forcibly  scraped  with  the  blunt  two- 
handled  tool  (Fig.  o),  by  which  it  is  put  into  a  better 
condition  for  liming.  The  effect  of  the  scraping  or  rub- 
bing is  to  break  down  the  fleshy  matter  attached  to  the 
skin,  which  had  become  hardened  during  the  process  of 
drying,  and  thus  render  the  skin  more  readily  acted  upon 
by  milk  of  lime. 

Liming. — After  the  skins  have  been  broken  they  are 
immersed  for  two  or  three  days  in  "old"  lime  liquor, 
being  "drawn"  occasionally,  that  is,  removed  from  the 
pits  by  means  of  the  small  tongs  (Fig.  48)  and  placed  in  a 
heap,  being  allowed  there  to  remain  for  some  time,  after 
which  they  are  steeped  in  "middling"  lime  liquor  for 
Several  days,  and  are  finally  immersed  in  strong  lime 
liquor,  in  which  they  remain,  being  frequently  drawn  as 
before,  until  the  hair  can  be  readily  removed  from  the  pelt 
by  the  finger.  In  from  ten  to  fourteen  days,  according  to 
the  temperature  of  the  atmosphere,  the  skins  are  ready 


308  LEATHER  MANUFACTURE. 

for  impairing.  When  the  liming  process  is  complete,  the 
workman  passes  his  thumb  along  the  upper  surface  of  the 
skin,  when  the  cuticle,  with  its  hair,  peels  off  with  perfect 
ease,  exposing  the  bare  pelt  or  corium. 

Unhairing, — The  skins,  after  being  removed  from  the 
lime-pits  or  tanks,  are  allowed  to  drain  for  a  short  time, 
when  they  are  removed  to  the  beam-room,  where  they  are 
submitted  to  the  process  of  unhairing,  after  which  they 
are  again  soaked  in  lime  water  for  several  days.  They  are 
next  fleshed,  by  which  the  pelt  is  brought  to  a  tolerably 
clean  condition.  The  lengthened  steeping  in  the  lime 
liquor,  however,  has  the  effect  of  forcing  the  lime  into  the 
pores  of  the  skin  to  such  an  extent  that,  unless  this  were 
removed,  the  materials  subsequently  employed  would  not 
enter  into  the  interior  structure  of  the  skin.  To  remove 
this  lime  and  to  open  the  pores,  the  kid  skins  are  immersed 
in  the  bran  drench. 

The  Bran  Drench  is  a  mixture  of  bran  and  water,  con- 
sisting of  about  40  Ibs.  of  bran  to  20  gallons  of  water, 
which  is  allowed  to  undergo  what  is  called  acetous  fermenta- 
tion, during  which  acetic  acid  is  formed.  By  the  action  of 
the  vegetable  acid  the  lime  within  the  pores  of  the  pelt  is 
converted  into  soluble  acetate  of  lime,  which  is  removed  by 
subsequent  washings.  The  skins  are  steeped  in  the  bran 
liquor  for  some  days,  being  frequently  turned  over,  so  as 
to  equalise  the  action  of  the  sour  liquor.  The  branning 
operation  is  watched  with  great  care,  especially  when 
treating  such  delicate  skins  as  those  of  the  kid.  The 
branning  has  the  effect  of  opening  the  pores  of  the  skin 
besides  "  killing  "  the  lime,  as  it  is  termed. 

Striking. — When  the  skins  are  sufficiently  branned  they 
are  next  struck,  or  scudded,  by  being  worked  on  the  beam 
with  the  blunt  knife,  by  which  albuminous  matters,  and 
any  lime  that  may  still  remain  within  the  pores,  is  effec- 
tually worked  out.  The  skins  are  then  again  steeped  in 
the  bran  drench  for  a  day  or  two,  after  which  they  are  in 
a  condition  to  undergo  the  process  of  aluming. 

Treatment  with  Alum  and  Salt. — In  this  operation  the 
ekins  are  put  into  a  kind  of  wooden  drum  or  tumbler 


WHITE  ^EATHER. 


309 


51. 


(Fig.  51).  This  machine,  which  is  furnished  with  a  door, 
either  in  its  circumference  or  at  one  of  its  ends,  through 
which  the  skins  and  alum 
mixture  are  thrown,  is 
constructed  so  as  to  rotate 
upon  an  iron  axle  with 
the  usual  gearing.  In  the 
interior  of  the  tumbler 
are  fixed,  at  equal  dis- 
tances, a  series  of  per- 
forated breakers,  upon 
which  the  skins,  when 
the  machine  is  in  motion, 
fall,  and  thus  become 
more  intimately  brought 
in  contact  with  the  alum 
mixture.  These  drums 
are  also  used  for  washing 
the  skins.  On  each  end 
of  the  drum  are  four  small  holes  to  admit  cold  air  from 
without,  and  to  allow  the  air  warmed  by  the  rotary  motion 
of  the  drum  to  escape.  The  materials  placed  in  the  drum 
to  act  upon  the  skins  for  the  inferior  kinds  of  leather  are 
alum  and  salt,  in  the  proportion  of  about  12  Ibs.  of  alum 
and  2  J  Ibs.  of  salt  to  about  12  gallons  of  water  for  each 
200  skins.  Sometimes,  instead  of  employing  the  tumbler, 
the  alum  mixture  is  placed  in  a  tub,  and  the  skins  steeped 
in  the  solution.  Whichever  method  is  adopted,  the  skins 
are  only  subjected  to  the  action  of  the  mixture  for  about 
five  minutes,  by  which  time  the  desired  effect  is  produced. 
Egging — The  Emulsion  or  Paste. — For  skins  destined 
to  form  the  finest  quality  of  glove  leather,  a  peculiar  kind 
of  emulsion  is  employed,  in  which  the  yolks  of  eggs  form 
a  necessary  ingredient.  This  emulsion  is  prepared  by 
working  up  the  yolks  of  eggs,  in  the  proportion  of  one 
yolk  per  skin,  with  a  little  flour  and  water,  the  whole  being 
vigorously  worked  up  into  a  thin  paste.  Into  this  mixture 
the  skins  are  put,  one  by  one,  and  they  are  trampled  upon 
by  the  naked  feet  until  the  emulsion  has  become  thoroughly 


3io 


LEATHER  MANUFACTURE. 


absorbed.     The  effect  of  the  aluming  and  steeping  in  the 
emulsion  is  to  whiten   and  soften  them,  preventing  the 
latter  from  hardening  under  the 
process  of  drying. 

Drying. — The  tawed  skins  are 
next  hung  upon  poles  in  the  dry- 
ing-room, after  which  they  are 
stretched  out,  smoothed,  and  soft- 
ened upon  the  stake. 

Staking.— The  stake  (Fig.  52) 
is  a  wooden  support,  at  the  upper 
end  of  which  is  a  blunt  steel,  semi- 
circular blade,  somewhat  like  a 
cheese-knife.  The  skin,  in  a  nearly 
dry  state,  is  laid  over  this,  and  the 
workman  takes  hold  of  it  with  both 
hands  and  forcibly  draws  it  over 
the  knife  in  all  directions,  but  more 
especially  from  side  to  side,  by 
which  it  becomes  stretched  to  its 
fullest  extent,  while  at  the  same  time  all  stiffness  and 
rigidity  are  removed,  and  it  becomes  exceedingly  soft  and 
pliant. 

French  Kid  Leather.— The  following  method  of  pre- 
paring this  famous  leather  is  thus  given  by  Wagner  :*  "  The 
so-called  Erlanger,  or  French  tawing  process,  is  employed 
only  for  the  production  of  the  glace,  or  kid  leather,  used 
for  making  gloves  and  ball-room  shoes.  The  hair  side  of 
the  skins  intended  to  be  converted  into  this  leather  is  left 
unchanged,  while  as  regards  wash-leather  gloves,  which 
are  treated  (tanned)  with  fish  oil,  the  hair  side  is  cut  off. 
The  skins  intended  to  be  converted  into  kid  leathers  are 
treated  with  extraordinary  care,  and  thus  acquire  in  a  very 
high  degree  all  the  good  qualit}^  of  alum -tanned  (or  rather 
tawed)  leathers.  As  these  skins  are  often  intended  to  re- 
main white,  or  are  dyed  with  delicate  colours,  the  greatest 
care  is  taken  to  prevent  any  injury — as,  for  instance,  con- 

*  "A  Handbook  of   Chemical  Technology."      By  Rudolf  Wagner, 
rii.D.    Edited  by  William  Crookcs,  F.K.S. 


WHITE  LEATHER.  3" 

tact  with  oak  wood  or  with  iron  while  wet.  Two  kinds 
of  skins  are  employed  for  conversion  into  the  better  varie- 
ties of  kid  leather ;  one  of  these,  the  more  expensive, 
being  the  skins  of  young  goats  fed  solely  upon  milk,  tho 
other  being  lamb  skins.  Each  of  these  skins  yields  on  an 
average  two  pairs  of  gloves.  The  leather  of  which  ladies' 
ball-room  shoes  are  made  is  obtained  from  the  skins  of  young 
calves  (so  called  calf  kid).  The  preliminary  operations  of 
preparing  this  leather  are  exactly  similar  to  those  adopted 
for  ordinary  white  leather,  but  the  tawing  operations  are 
quite  different,  the  skins  being  put  into  a  peculiar  mixture 
by  which  they  are  not  only  tawed,  but  simultaneously  im- 
pregnated with  a  sufficient  quantity  of  oil  to  render  them 
soft  and  give  suppleness.  The  mixture  consists  of  a  paste 
composed  of  wheaten  flour,  yolks  of  eggs,  alum,  common 
salt,  and  water.  The  flour,  by  the  gluten  it  contains,  aids 
the  absorption  of  the  alumina  compound,  and  thus  assists 
the  real  tawing.  The  starch  does  not  enter  into  the  com- 
position of  the  skins,  while  the  yolk  of  eggs  acts  by  the  oil 
it  naturally  contains  in  the  state  of  emulsion,  this  oil 
giving  the  kid  leather  that  suppleness  and  softness  which 
is  so  much  esteemed  in  gloves. 

"  It  appears  that  emulsions  made  with  almond  oil  (the 
so-called  sweet  oil  of  almonds,  a  fixed  oil),  olive  oil,  fish 
oil,  and  even  paraffin,  may  be  advantageously  substituted 
for  the  yolk  of  eggs.  The  skins  are  thoroughly  soaked 
and  kneaded  in  this  mixture,  to  which,  in  France,  there  is 
sometimes  added  two  to  three  per  cent,  of  carbolic  acid,  for 
the  purpose  of  preventing  the  too  strong  heating  of  the  skins 
when  impregnated  with  the  mixture  and  packed  in  heaps. 
The  skins  are  next  stretched  out  by  hand  and  dried  as 
rapidly  as  possible,  by  exposure  to  air.  Having  been 
damped,  a  dozen  of  the  skins  are  placed  between  linen 
cloths  and  trodden  upon  to  render  them  soft.  After  this 
they  are,  one  by  one,  planed,  dried,  and  again  planed. 
Either  by  rubbing  with  a  heavy  polished  glass  disc,  or  by 
the  appr&eur,  simultaneously  with  the  application  of  some 
white  of  egg,  a  solution  of  gum,  or  of  fine  soap,  a  gloss  is 
given  to  the  skins,  the  hair  side  of  which  is  the  right  or 


312  LEATHER  MANUFACTURE. 

dyed  side.  The  dyes  are  applied  either  by  immersion  or 
by  brushing  over  the  leather,  the  latter  or  English  method 
of  dyeing  skins  being  more  generally  practised." 

Knapp  states  that  very  good  white  leather  may  be  pro- 
duced by  tawing  the  epidermis  from  lamb  or  goat  skins  in 
a  saturated  solution  of  stearic  acid  (stearin  e)  in  alcohol,  the 
leather  thus  produced  being  very  soft,  and  whiter  than 
ordinary  glace,  leather,  besides  having  a  beautiful  gloss. 

Imitation  Kid. — For  preparing  this  kind  of  leather 
lamb  skins  are  employed.  These  skins  are  imported  from 
the  shores  of  the  Mediterranean,*  "  in  the  wool/'  as  it  is 
termed,  and  this,  being  a  valuable  commodity,  is  removed 
with  very  great  care  before  the  operations  on  the  pelt 
commence.  Since  the  wool  would  be  impaired  if  the  skins 
were  subjected  to  the  process  of  liming,  the  skins  are  sub- 
mitted to  a  process  of  sweating,  or  putrefactive  fermenta- 
tion, by  which  the  wool  becomes  loosened  from  the  pelt. 

Sweating. — The  skins  are  first  steeped,  or  drenched,  in 
water  for  several  days,  after  which  they  are  broken  on  the 
flesh  side.  They  are  then  again  steeped,  drained,  and  while 
still  wet  are  transferred  to  a  close  room,  sometimes  an 
underground  vault,  the  temperature  of  which  remains  nearly 
uniform  all  the  year  round.  In  this  the  skins  are  sus- 
pended from  rails  or  bars.  After  a  certain  time  ferment- 
ation commences,  ammonia  being  given  off  in  considerable 
quantity,  together  with  a  powerful  and  offensive  odour. 
In  about  five  days  the  wool  becomes  loosened  from  the 
pelt,  but  the  skins  are  carefully  examined  from  time  to  time 
before  the  process  is  complete,  as  it  is  of  the  greatest  im- 
portance that  the  sweating  process  should  be  arrested  and 
the  skins  withdrawn  at  the  proper  period,  otherwise  the 
pelt  itself  would  suffer  injury  from  the  decomposition 
which  ensues. 

"When  the  sweating  is  completed,  the  skins  are  removed 
and  worked  on  the  beam,  or  slimed,  as  it  is  termed,  that  is 
scraped  on  the  flesh  side  with  the  beam  knife,  to  remove  a 
slimy  matter  which  exudes  from  the  pores.  The  wool  is 

*  These  skins  generally  measure  about  20  inches  by  12,  and  each  skin 
produces  leather  for  two  pairs  of  small  gloves. 


WHITE  LEATHER.  3»3 

then  removed,  and  this  is  afterwards  cleaned  and  prepared 
for  sale.  The  unwooled  pelts  are  next  steeped  in  the  lime- 
pit  for  about  a  week  to  "  kill"  the  grease,  and  after  this 
they  are  fleshed  on  the  beam.  This  having  been  done, 
they  are  next  placed  in  a  drench  of  sour  bran  liquor  for 
several  days  to  remove  the  lime  and  open  the  pores  ;  they 
are  next  treated  with  the  alum  mixture,  and  in  all  other 
respects  treated  in  the  same  way  as  kid  skins. 

Continental  Method  of  preparing  Glove  Leather. — 
The  substances  used  are  alum  and  common  salt  as  in  the 
ordinary  white  tanning,  but  it  is  especially  necessary  to 
obtain  alum  free  from  iron,  on  which  account  this  is  selected 
in  the  most  careful  manner.  Wheat  flour  and  the  yolks 
of  eggs  are  then  added  in  the  following  proportions.  For 
a  thousand  skins  of  young  goats  or  lambs,  25  Ibs.  of  alum 
free  from  iron  and  11  Ibs.  of  common  salt  are  dissolved 
in  150  Ibs.  of  water.  Next,  a  firm  stiff  dough  is  prepared 
from  the  yolks  of  500  fresh  eggs  and  50  Ibs.  of  the  very 
finest  wheat  flour,  to  which  only  enough  of  the  alum  solu- 
tion is  added  to  enable  the  dough  to  be  mixed.  When  the 
egg-yolks  and  the  flour  have  become  very  thoroughly 
and  intimately  blended,  the  remainder  of  the  solution  is 
gradually  added,  forming  a  thin  pap  of  about  the  consist- 
ence of  honey.  This  pap  is  called  nahrung  (nourishment, 
or  food).  Instead  of  the  egg-yolks  it  is  very  common  in 
southern  France  to  employ  pure  olive  oil,  but  even  there, 
where  hens  are  scarce  and  eggs  dear,  the  eggs  are  employed 
by  way  of  assistance  when  the  finest  kind  of  leather  is  to 
be  prepared.  The  nahrung,  or  tawing  paste,  is  placed 
in  a  vat,  in  which  the  skins  are  laid,  being  turned  over 
several  times,  soaked  through,  and  then  a  couple  of  per- 
sons with  well- cleaned  bare  feet  go  into  the  vat  and  tramp 
about  for  an  hour  until  the  liquid  part  of  the  paste  has 
been  entirely  taken  up.  After  this  has  been  effected  other 
workmen  relieve  the  tired  trampers,  and  repeat  the  opera- 
tion with  the  skins  which  have  already  absorbed  sufficient 
of  the  liquor.  Next  follows  the  stretching  of  the  leather. 
Two  workmen  grasp  a  skin  with  both  hands  and  pull  it  in 
every  direction  as  powerfully  as  possible  without  tearing 


3H  LEATHER  MANUFACTURE. 

it.  The  skins  are  then  dried  quickly  and  given  their 
lustre  by  covering  the  grain  side  with  the  whites  of  eggs 
and  rubbing  them  with  a  small  disc  of  glass. 

The  wheat  flour  used  in  making  the  paste  has  no  effect 
upon  the  skin,  and  is  only  employed  as  a  medium  for  dis- 
tributing the  egg,  oil,  and  alum  evenly  and  more  finely, 
and  to  present  the  alum  as  well  as  the  oil  (which  are  both 
necessary  for  the  tawing)  in  the  form  of  an  emulsion, 
not  too  thin,  otherwise  the  action  upon  the  skin  would  be 
too  rapid,  and  therefore  irregular.  The  claim  that  the 
flour  serves,  by  means  of  its  starch  constituent,  to  give  the 
leather  a  white  colour,  could  only  be  made  by  one  who  was 
entirely  unacquainted  with  the  matter.  The  starch  flour 
does  not  dye  white ;  it  covers  the  outer  surface  with  white 
flakes,  which  fall  off  as  soon  as  it  dries. 

This  fine  leather  has  yet  to  be  coloured  ;  for  this  pur- 
pose it  is  sorted  into  five  or  six  different  grades.  Those 
skins  which  are  entirely  free  from  faults  are  allowed  to 
remain  white,  being  used  for  white  gloves.  Since  these 
are  the  most  delicate,  they  must  also  be  the  most  free  from 
faults.  The  second  sort  are  employed  for  very  clear 
colours,  as  yellow,  chamois,  flesh  colour,  or  rose-red.  The 
third  sort  is  coloured  dark  yellow,  lilac,  or  sea-green ;  and 
the  fourth  or  stronger  colours,  brown,  violet,  ash-gre}7",  and 
green.  The  fifth  grade  is  employed  for  all  dark  shades, 
and  the  sixth  for  black.  The  colour  is  applied  either  by 
immersing  the  whole  skin,  as  is  done  with  the  lighter 
colours,  or  by  rubbing  the  dye  upon  the  grain  side,  which 
is  the  practice  with  the  lighter  tints,  in  order  that  the 
colour  may  not  come  off  upon  the  hand  when  it  becomes 
warm.  The  clear  colours  do  not  "  crock  "  so  easily,  and 
the  little  that  does  come  off  is  hardly  noticeable. — Gerber 
Courier. 

Calf  Kid  for  Uppers. — The  preliminary  operations  in  the 
preparation  of  this  famous  leather  are  :  1,  Soaking  and 
cleansing;  2,  Liming;  3,  Unhairing  and  fleshing;  4, 
Puring ;  5,  Scudding ;  6,  Drenching.  The  skins  are 
next  subjected  to  a  series  of  operations  termed  dressing, 
the  most  important  being  :  1,  Alum  dressing ;  2,  Drying; 


WHITE  LEATHER.  315 

3,  Seasoning ;    4,  Staking  ;    5,  Shaving  ;    6,   Egging ;   7, 
Dyeing  and  finishing. 

Soaking  and  Liming. — As  the  skins  are  received  from 
the  slaughter-house,  they  are  thrown  into  a  large  tub  of 
water  to  cleanse  them  from  filthy  matters,  after  which  they 
are  placed  in  the  old  lime-pits,  in  which  they  are  handled 
as  usual,  after  which  they  are  treated  in  a  stronger  or 
" middle "  lime,  in  which  they  are  again  handled;  and 
are  afterwards  immersed  in  strong  lime,  where  they  are 
allowed  to  remain  (being  drawn  each  day  and  returned  to 
the  same  pit)  until  the  hair  is  sufficiently  loosened,  when 
the  skins  are  drawn  and  allowed  to  drain,  after  which 
they  are  removed  to  the  beam-house  to  be  unhaired  and 
fleshed. 

*Unhairing  and  Fleshing  by  Machinery. — We  had  re- 
cently the  pleasure,  through  the  courtesy  of  Mr.  John  S. 
Carlaw,  of  Blue  Anchor  Lane,  Bermondse}T,  of  witnessing 
the  unhairing  and  fleshing  of  calf  skins  by  a  machine  of 
remarkable  effectiveness.  The  blades  of  this  machine, 
which  is  called  the  "Duplex  Unhairing  and  Fleshing  Ma- 
chine "  (Janson's  patent),  are  the  invention  of  M.  V.  Gal- 
lien,  and  so  constructed  as  to  act  upon  the  two  surfaces  of  a 
skin,  removing  hair  and  flesh  simultaneously,  without  in  the 
least  degree  injuring  the  pelt.  The  inventor  says  :  "  The 
object  of  this  invention  is  to  give  such  an  edge  to  the 
knives  or  blades  of  revolving  cylinders  in  machinery,  for 
shaving  or  otherwise  treating  hides  and  skins,  that  there 
may  be  little  danger  of  making  too  deep  a  cut  into  the 
hide  or  skin,  that  the  work  may  be  done  more  efficiently 
than  hitherto,  and  that  the  edge  may  be  renewed  with 
great  facility.  For  this  purpose  an  edge  is  given  to  these 
cylinder  blades  similar  to  that  used  on  the  ordinary  cur- 
rier's or  beamsman's  shaving  knife,  that  is  to  say,  the  edge 
is  slightly  bevelled,  and  in  the  bevelling  a  very  thin  feather 
or  '  burred '  cutting  edge  is  formed  by  the  thread  or  turn- 
over of  the  metal.  This  thread  or  cutting  edge  may  be 
constantly  renewed  by  simply  reversing  the  movement  of 
the  cylinder,  and  bringing  the  blades  into  contact  with  an 
emery  plate,  file  or  other  sharpener,  throwing  up  the 

*  Sec  Chap.  xxxi.  on  Machinery  Employed  in  Leather  Manufacture  for 
more  recent  information.— ED.  Fifth  Edition. 


316  LEATHER   MANUFACTURE. 

feather  or  thread,  which  is  then  adjusted  by  the  ordinary 
tool  or  '  steel/  ' 

The  Duplex  Unhairing  Machine  has  been  practically 
adopted  by  Mr.  Carlaw  for  a  considerable  time,  and  has 
proved  to  be  a  most  satisfactory  piece  of  mechanism.  Mr. 
Carlaw,  who  frequently  operates  the  machine  himself, 
informs  us  that  he  can  readily  unhair  and  flesh  in  one 
operation,  two  and  a  half  dozen  calf  skins  per  hour,  or  one 
in  every  two  minutes,  and  the  ease  with  which  this  is 
accomplished  is  really  surprising.  On  examining  some  pelts 
after  they  had  passed  through  the  machine  we  were  much 
pleased  with  the  perfect  uniformity  and  regularity  with 
which  the  machine  had  done  its  work.  A  very  useful 
feature  in  this  remarkable  apparatus  is  that  the  pelts  are 
washed  at  the  same  time  they  are  being  unhaired  and 
fleshed,  by  a  series  of  jets  of  water  issuing  from  per- 
forated horizontal  tubes,  which  play  upon  both  sides  of 
the  skin.  .  After  passing  through  the  machine  the  skins 
are  thrown  into  a  tub  of  water  until  required  for  the  next 
operation. 

Puring. — The  pure — which  is  a  lixivium  of  pigeons' 
dung  in  water — is  kept  in  large  tubs,  and  in  this  the  un- 
haired skins  are  placed  and  allowed  to  remain,  with  fre- 
quent turning  over,  until  they  acquire  a  certain  texture, 
by  which  the  workman  judges  the  operation  to  be  com- 
plete, when  they  are  removed  and  submitted  to  the 
operation  of  scudding. 

Scudding. — The  object  of  this  operation  is  to  remove  a 
film  which  remains  upon  the  pelt  after  the  hair  has  been 
removed,  and  also  to  force  out  from  the  skin  the  salts  of 
lime  formed  by  the  action  of  the  pure  upon  the  lime 
absorbed  by  the  skins  in  the  lime-pits.  The  "  scud  "  is 
removed  by  working  the  pelt  upon  the  beam  with  the  blunt 
knife,  and  after  scudding  the  pelts  are  thrown  into  a  large 
tub  containing  the  bran  drench. 

Drenching. — The  skins  are  allowed  to  remain  in  the 
bran  drench — which  is  kept  in  an  active  state  of  acetous 
fermentation — until  the  workman  judges  that  the  desired 
effect  is  produced,  which  is  determined  by  the  appearance 


WHITE  LEATHER.  317 

and  feel  of  the  pelt  under  pressure  of  the  fingers.  When 
the  skins  are  first  thrown  into  the  drench,  they  sink  to 
the  bottom  of  the  vessel,  but  as  fermentation  progresses 
(which  is  evidenced  by  a  brisk  evolution  of  carbonic  acid 
gas)  the  skins  rise  to  the  surface,  and  the  liquid  becomes 
covered  with  a  white  froth  or  foam.  After  drenching  the 
pelts  are  handed  over  to  the  dresser,  in  whose  hands  they 
undergo  the  subsequent  operations  which  convert  them 
into  tawed  leather. 

Alum  Dressing. — A  solution  of  alum  and  salt,  consisting 
of  three  parts  of  alum  to  four  parts  of  salt,  dissolved  in 
water,  is  prepared  and  placed  in  large  tubs,  and  in  these 
the  skins  are  placed  and  subjected  to  its  action  for  about 
two  weeks,  or  until  the  skins  are  properly  "  leathered/' 
which  is  ascertained  by  pressing  folds  of  the  skin  between 
the  fingers,  when,  if  the  sharp  bend  of  the  skin  assumes  an 
opaque  white  streak,  and  not  transparent,  the  skin  is 
known  to  be  properly  tawed — not  tanned,  as  some  will 
persistently  call  it. 

Drying. — The  alumed  skins  are  next  hung  up  in  the 
drying-room,  or  stove,  as  it  is  sometimes  termed,  until 
quite  dry,  when  they  are  called  "  crust  goods/*  from  their 
exceeding  hardness. 

Seasoning. — The  dried  skins  are  next  soaked  in  water 
for  a  short  time,  to  season  them  for  the  process  of  staking, 
which  is  thus  performed : — 

Staking. — The  skin  is  laid  across  the  perch,  and  the 
workman  takes  the  stake,  or  "  crutch  "  stake  as  some  call 
it,  in  his  hand,  and  placing  the  cross-handle  under  his 
right  arm,  holds  the  upright  stock  firmly  in  his  hand, 
while  with  the  left  hand  he  seizes  a  corner  of  the  skin, 
and  forces  the  blade  of  the  tool  (which  somewhat  resembles 
the  blade  of  a  blunt  cheese  knife)  from  above  downward, 
by  which  means  he  not  only  stretches  the  skin,  but  also 
renders  it  exceedingly  soft  and  pliant. 

Shaving. — The  skins  are  next  shaved,  either  by  hand  or 
by  the  shaving  machine  (Fig.  67),  by  which  the  flesh  side 
becomes  uniformly  levelled  by  reducing  the  substance  of 
the  stouter  parts. 


3i8  LEATHER  MANUFACTURE. 

Egging. — The  shaved  skins  are  now  ready  for  the  egg- 
paste  or  emulsion,  which,  with  the  skins,  is  put  into  a  re- 
volving tumbler,  and  the  machine  kept  in  motion  until 
the  skins  have  thoroughly  absorbed  the  composition,  when 
they  are  withdrawn,  stretched  out,  and  conveyed  to  the 
dyeing-room. 

Dyeing. — The  skins  are  first  "  mordanted  "  by  being 
put  into  a  tank  containing  urine,  after  which  they  are 
drained  and  folded  lengthwise,  flesh  side  inward.  They 
are  next  placed  in  a  tray  containing  a  hot  solution  of  log- 
wood. From  this  they  are  transferred  to  a  second  tray, 
containing  a  solution  of  sulphate  of  iron  (copperas),  which, 
with  the  former  treatment,  stains  the  grain  of  a  deep  blue- 
black.  The  dyed  skins  are  now  laid  over  a  horse  or 
tressel  to  drain,  after  which  they  are  hung  in  the  drying- 
room,  where  they  are  allowed  to  dry  gradually.  When 
dry  they  are  again  seasoned  with  water,  to  prepare  them 
for  grounding,  which  operation  is  performed  by  scraping 
the  flesh  side  with  the  "  moon-knife/'  a  tool  somewhat 
resembling  the  round  knife,  but,  being  furnished  with  a 
horizontal  handle  at  the  lower  part  of  the  aperture,  this 
tool  is  held  in  one  hand,  whereas  the  round  knife  is  held 
by  both  hands.  The  workman  holds  a  corner  of  the  skin 
depending  from  the  perch  with  his  left  hand  while 
scraping  the  skin  with  the  moon-knife.  After  grounding 
the  skins  are  laid  flat  on  a  bench  or  table,  grain  or  coloured 
side  up,  and  are  then  ironed  with  hot  irons,  much  in  the 
same  way  as  linen.  The  skins  are  then  sorted  into  sizes 
for  market. 

White  Sheep  Leather. — The  unwooled  skins,  as  they 
are  received  from  the  fellmonger,  are  first  steeped  in  the 
lime-pits  to  swell,  soften,  and  cleanse  them,  being  repeatedly 
drawn  and  allowed  to  drain  upon  inclined  tables,  which 
operations  are  continued  for  about  three  weeks.  The  skins 
are  next  rubbed  on  the  grain  side  with  a  whetstone  fixed 
into  a  wooden  case  with  two  handles,  in  order  to  free  them 
from  any  adhering  filaments  of  wool.  They  are  then 
ready  for  the  bran  steep,  which  is  made  by  mixing  40  Ibs. 
of  wheat  bran  in  20  gallons  of  water ;  in  a  short  time 


WHITE  LEATHER.  319 

fermentation  supervenes,  when  acetic  and  other  acids  are 
liberated,  which  convert  the  lime  within  the  pores  of  the 
skin  into  soluble  salts,  which  subsequent  working  on  the 
beam,  alternated  by  washings,  removes.  It  is  usual  to 
add  some  old  bran  liquor  to  the  bran  steep,  to  promote 
acetous  fermentation.  During  the  time  that  the  skins  are 
in  the  steep  they  require  to  be  frequently  turned  over, 
with  careful  watching,  otherwise  the  pelts  will  suffer 
considerably  from  the  action  of  the  vegetable  acids  present 
in  the  fermenting  liquor.  In  about  two  days  in  summer, 
and  eight  days  in  winter,  the  skins  are  said  to  be  raised. 
At  the  end  of  from  two  to  three  weeks  they  are  ready  for 
the  next  operation,  termed  aluming  or  alum  dressing. 

Aluminy. — The  alum  bath  for  a  hundred  skins  is  com- 
posed of  from  14  to  18  Ibs.  of  alum  and  from  2£  to  3  Ibs. 
of  common  salt,  which  are  placed  in  a  copper  with 
12  gallons  of  water.  When  the  mixture  begins  to  boil, 
three  gallons  of  it  are  passed  through  a  colander  into  a  tub, 
and  into  this  twenty- six  skins  are  introduced  and  worked 
one  after  another.  After  draining  they  are  put  together  in 
the  bath,  and  left  therein  for  about  ten  minutes  to  further 
absorb  the  liquor.  They  are  now  ready  for  the  next 
operation,  which  consists  in  treating  them  with  a  paste 
composed  of  flour  and  yolk  of  egg. 

The  Paste. — This  is  formed  by  mixing  (for  a  hundred 
skins)  about  14  Ibs.  of  wheat  flour  with  the  yolks  of  fifty 
eggs  in  the  following  way  :  the  alum  bath  through  which 
the  skins  have  been  passed  is  first  warmed,  when  the  flour 
is  sprinkled  into  it  and  well  stirred  in  ;  the  paste  is  well 
kneaded  by  additions  of  the  solution,  and  it  is  then  passed 
through  a  colander,  by  which  it  becomes  smooth  and  clear. 
The  yolks  of  eggs  are  next  added,  and  the  whole  thoroughly 
well  mixed  by  careful  and  vigorous  stirring.  The  skins 
are  first  worked  one  after  another  in  this  paste,  and  then 
the  whole  number  are  placed  together  in  the  -mixture,  in 
which  they  are  allowed  to  remain  for  a  day.  They  are 
afterwards  removed  one  by  one,  stretched  upon  poles,  and 
left  in  the  drying  loft  for  a  week  or  ten  days,  according  to 
the  season  and  the  thickness  of  the  skins. 


320  LEATHER  MANUFACTURE. 

The  effects  of  the  paste  are  that  the  skins  become 
whitened,  softened,  and  protected  from  the  hardening 
influence  of  the  atmosphere,  to  which  the  oily  matter  of 
the  eggs  largely  contributes.  But  for  this  treatment  the 
skins  would  be  unable  to  bear  the  severe  processes  of 
stretching  or  staking  to  which  they  are  afterwards  sub- 
jected to  render  them  soft  and  pliant. 

Staking. — Before  being  worked  on  the  stake  (Fig.  52) 
the  skins  are  steeped  for  a  short  time  in  clean  water ;  the 
workman  then  takes  a  skin  and  works  it  to  and  fro,  flesh 
side  downwards,  over  the  semi-circular  knife  or  blade  of 
the  stake  with  considerable  force,  by  which  it  becomes 
stretched  in  length  in  the  proportion  of  five  to  three.  By 
this  operation  the  whiteness  of  the  skin  is  greatly  im- 
proved, while  it  acquires  the  utmost  degree  of  suppleness 
which  it  is  susceptible  of  attaining.  The  skins  are  after- 
wards stretched  by  hooks  and  strings  and  hung  up  to  dry. 
When  dry  they  are  worked  on  the  stretching-iron,  or  they 
are  polished  with  pumice-stone.  Sometimes  a  yellowish 
tint  is  given  to  the  skins  by  a  mixture  of  whiting  and 
yellow  ochre  in  a  moist  state  rubbed  over  the  grain.  After 
pumicing,  the  skins  are  smoothed  with  a  hot  iron,  in  the 
same  way  that  linen  is  ironed,  b}^  which  the  grain  assumes 
a  brilliant  and  glossy  surface. 

Large  sheep  skins  are  also  extensively  converted  into 
white  leather  by  the  process  of  tawing  with  alum  and 
salt,  for  aprons  used  by  workmen  employed  in  iron  works, 
which  are  found  to  resist  the  action  of  heat  better  than 
tanned  leather.  Sometimes  also  these  skins  are  partially 
tanned  with  bark,  and  afterwards  treated  with  alum  and 
salt,  for  making  leggings,  gaiters,  coarse  gloves,  &c.,  used 
by  farmers  and  agricultural  labourers.  This  latter  trade 
is  now  chiefly  carried  on  in  the  provinces. 

Splitting  Sheep  Skins. — Amongst  the  many  ingenious 
contrivances  employed  in  the  manufacture  of  the  different 
kinds  of  leather,  none  probably  is  so  remarkable  as  the 
machine  which  is  capable  of  cutting  or  splitting  an 
unhaired  skin  into  two  or  even  three  sections,  without 
forming  holes  in  either  section.  Although  there  are 


WHITE  LEATHER.  321 

several  modifications  of  the  splitting  machine — originally 
adopted,  we  believe,  by  the  eminent  firm  of  Bevington 
and  Sons — a  description  of  their  now  famous  machine  will 
doubtless  suffice  to  indicate  the  principle  upon  which  skins 
are  subdivided  by  machinery.  The  following  details  of 
this  important  machine  are  taken  from  an  interesting 
work  entitled  Days  at  the  Factories  : — 

"  Two  rollers  (Fig.  53)  ranged  horizontally  in  a  frame 
are  made  to  rotate  in  opposite  directions,  the  vacancy 
between  them  being  only  just  sufficient  to  admit  a  soft 
wetted  sheep  skin  or  pelt.  The  rotation  of  the  rollers  causes 
the  skin  to  be  drawn  slowly  between  these  ;  but  it  cannot 
do  so  without  encountering  the  blade  of  a  very  sharp  knife 
which  has  a  reciprocating  horizontal  motion,  in  such  a 
position  as  to  cut  the  skin  into  two  thicknesses  as  it 
passes  the  knife,  one  half  passing  over  and  the  other 
under  the  blade,  a  most  ingenious  contrivance  for  yielding 
to  any  inequalities  which  may  occur  in  the  skin.  One  of 
the  rollers  is  made  in  several  pieces,  so  adjusted  that  in 
passing  over  any  thickened  portions  of  the  skin  the 
common  aperture  between  the  rollers  is  widened  at  that 
part.  It  is  one  of  the  peculiarities  in  the  construction  of 
the  machine  that  one  of  the  semi-thicknesses  or  sections 
of  the  skin  must  be  equable  and  level  in  every  part,  while 
the  irregularities  which  might  have  existed  in  the 
original  skin  will  be  thrown  into  the  section.  Either 
section,  the  '  grain '  side  or  the  *  flesh '  side,  may  have 
this  equable  thickness  given  to  it  according  to  the  mode 
in  which  the  skin  is  adjusted  on  the  rollers  ;  and  the  two 
portions  may  have  various  ratios  given  to  their  thickness 
according  to  the  position  of  the  vibrating  knife  opposite 
the  opening  between  the  rollers.  A  sheep  skin  of  the 
usual  size  occupies  about  two  minutes  in  splitting,  during 
which  time  the  knife  makes  from  2,000  to  3,000  vibratory 
motions  to  and  fro,  cutting  a  minute  portion  of  the  skin 
at  each  movement." 

A  representation  of  skin- splitting  is  shown  in  the  sketch 
(Fig.  53).  These  machines  are  now  made  to  split  skins 
into  three  equal  sections  or  slices,  the  grain  being  used 

Y 


322  '  LEATHER  MANUFACTURE. 

for  skiver,  the  middle  portion  for  parchment,  and  the  flesh 


Fig.  53. 

side,  being  of  unequal  surface,  and  therefore  unsuited  for 
conversion  into  leather,  being  used  for  glue-making.    The 


Fig.  54. 

American  Union  Splitting  Machine,  used  to  some  extent 
for  splitting  tanned  leather,  is  shown  in  Fig.  54.* 

*  See  also  Chap.  xxxi.  p.  412.— ED.  Fifth  Edition. 


CHAPTER  XXVII. 
CHROME  LEATHER  MANUFACTURE. 

Preliminary  Operations. — Liming  and  Unhairing. — Fleshing.— Paring 
or  De-liming. — Scudding. — Chroming  Operations. — Strikiug-out  and 
Shaving.  —  Dyeing  Chrome  Leather.  —  Fat-Liquoring.  —  Dyeing 
Black. — Putting  or  Striking  Out. — Oiling  and  Drying. — Stukiug  or 
Softening. — Seasoning. — Glazing. 

IN  the  development  of  what  is  known  as  the  chrome 
process,  the  past  few  years  have  witnessed  a  complete 
revolution  in  leather-making,  and  one  which  has  had 
far-reaching  consequences  upon  the  producing  and  con- 
suming side  of  leather  manui'acture  in  glace  kid,  box  and 
willow  calf,  sides,  belting  and  harness,  &c.  We  have 
had  an  absolute  departure  from  the  older  forms  of  tanned 
leathers,  and  it  is  only  fair  to  describe  the  success  of 
chrome  leathers  as  the  outcome  of  American  perseverance 
and  ingenuity  in  exploiting  technical  chemistry  for  the 
purposes  of  commercial  industry. 

Only  a  few  years  ago  the  man  who  ventured  to  express 
his  belief  that  "  chemicals  "  would  take  the  place  of  oak 
bark  for  leather-making  was  looked  upon  as  a  dreamer; 
now  the  French  tanner  of  bark  upper  leather  is  largely 
displaced,  America  has  captured  the  cream  of  the  world's 
glace  leather  trade,  and  British  and  Continental  manu- 
facturers have  taken  up  chrome  leather-making  with  a 
fair  amount  of  success. 

It  may  be  permissible  here  to  briefly  summarise  the 
history  and  technique  of  the  process,  for  it  is  certain 
much  of  the  business  of  the  leather  manufacturer  of  the 


324  LEATHER  MANUFACTURE. 

future  will  depend  upon  the  successful  catering  for  this 
particular  branch  of  the  industry. 

As  far  back  as  1858,  the  late  Professor  Knapp  brought 
out  a  chrome  process,  but  it  created  little  notice  in  the 
industrial  world,  and  was  regarded  as  of  only  chemical 
interest.  In  1879,  Heinzerling  patented  a  form  of  chrome 
leather ;  this,  again,  attracted  little  attention,  and  it  was 
left  to  the  ingenuity  of  August  Schultz,  of  New  York,  to 
bring  out  an  idea  commercially  valuable.  His  patent 
was  dated  January  8,  1884 ;  and  although  it  has  now 
expired,  it  has  been  the  subject  of  endless  litigation  in 
America,  which  always  ended  in  favour  of  the  patentee. 


THE  ORIGINAL  SCHULTZ  PATENT. 

Briefly  put,  the  principle  of  the  chrome  tannage  de- 
pends upon  the  formation  of  chromic  oxide  in  the  skin, 
this  being  brought  about  by  the  reduction  of  chromic 
acid  with  suitable  agents.  As  a  good  deal  of  the  lighter 
class  of  chrome  leather  is  still  made  in  much  the  same 
way  as  by  Schultz's  method,  it  will  be  advantageous  to 
give  here  his  original  specification. 

"This  invention  relates  to  a  new  process  for  tawing 
hides  or  skins,  said  process  consisting  in  subjecting  said 
hides  or  skins  to  the  action  of  compounds  of  metallic 
salts — such  as  bichromate  of  potash — and  then  treating 
the  same  with  hyposulphite  of  soda,  by  which  term  is 
understood  that  salt  which  is  more  recently  sometimes 
called  *  thiosulphate  of  soda '  (Na2S203). 

"In  carrying  out  my  process  I  unhair  the  raw  hides 
and  prepare  them  in  the  same  manner  in  which  they  are 
made  *  ready  '  for  tanning.  If  the  hides  have  not  been 
pickled,  I  subject  them  to  the  action  of  a  solution  of 
bichromate  of  potash  in  the  presence  of  an  acid — such  as 
hydrochloric  acid — or,  if  the  hides  have  been  pickled 
they  may  be  treated  in  a  solution  of  bichromate  of  potash 
in  water  without  the  addition  of  an  acid. 

"In  this  solution  the  hides  are  left  for  a  shorter  or 


CHROME  LEATHER  MANUFACTURE.  325 

longer  time,  according  to  their  thickness  and  to  the 
strength  of  the  solution  employed.  A  skiver  or  the  face 
of  a  sheep  skin  can  be  done  in  a  strong  solution,  as  above 
described,  in  about  fifteen  minutes,  while  a  full  skin 
'  roan '  would  require  in  the  same  solution  about  one 
hour.  I  call  the  solution  'weak'  if  it  contains  5  per 
cent,  or  less  of  the  weight  of  skins  of  bichromate  of 
potash,  and  I  call  the  solution  '  strong '  if  it  contains 
more  than  5  per  cent,  of  bichromate  of  potash.  It  is 
not  material,  however,  how  strong  the  solution  is. 

"  The  skins  are  completed  if  small  pieces  cut  from 
the  thickest  parts  of  said  skin  show  that  the  solution 
lias  entirely  penetrated.  The  skins  are  then  ready  to 
be  taken  out,  and  after  the  adhering  liquor  has  run  off, 
the  skins  are  introduced  into  the  second  solution,  which 
consists  of  hyposulphite  of  soda  dissolved  in  water,  and 
adding  an  acid,  such  as  hydrochloric  acid.  The  solution 
may  be  strong  or  weak  of  hyposulphite,  and  the  quantity 
of  acid  used  at  first  may  be  less  than  requisite  to  split  up 
the  entire  quantity  of  hyposulphite,  and  more  acid  may 
be  added  if  the  skins  show  that  more  is  required,  which 
is  indicated  by  the  colour  of  the  skins.  When  they 
are  done  they  show  a  whitish,  bluish,  or  greenish  colour, 
according  to  the  time  they  are  kept  in  the  hyposulphite 
solution. 

"A  skiver  which  first  has  been  exposed  to  the  action 
of  the  bichromate  for  fifteen  minutes  will  be  ready  by 
remaining  in  the  hyposulphite  solution  about  twenty 
minutes.  For  thicker  skins  a  proportionately  longer 
time  is  required.  For  some  skins — such  as  calf  or  steers' 
skins — it  is  desirable  that  the  same,  after  having  been 
withdrawn  from  the  second  or  hyposulphite  solution,  shall 
be  returned  to  the  bichromate  solution,  which  imparts  to 
them  a  brownish  colour,  and  leaves  them  in  a  favourable 
condition  to  be  coloured  black.  The  colouring  can  be 
done  after  the  skins  leave  the  hyposulphite  solution,  and 
after  they  have  been  exposed  for  the  second  time  to  the 
bichromate  solution.  The  leather  coming  from  the 
hyposulphite  solution  is  especially  adapted  for  light  or 


326  LEATHER  MANUFACTURE. 

dark  colours,  and  by  proper  dyeing  methods  better  and 
brighter  colours  can  be  produced  than  on  leather  done  by 
tannin.  After  the  leather  is  treated  in  the  manner  above 
indicated,  it  may  be  coloured,  soaped,  and  greased  in  the 
usual  way. 

"  Leather  can  also  be  made  by  reversing  the  operation 
and  first  soaking  the  hides  in  a  solution  of  hyposulphite 
of  soda  and  then  exposing  them  to  the  action  of  the 
bichromate  solution.  By  using  the  solutions  indicated 
at  a  heat  of  about  80°  Fahr.,  the  process  will  be  done  in 
a  shorter  time  than  if  the  solutions  are  used  cold. 

"  By  my  process  the  gelatine  contained  in  the  hides  is 
rendered  insoluble  by  means  not  injurious  to  the  leather. 
If  leather  made  by  tannin  is  put  in  a  strong  soda  solution, 
the  tannin  is  extracted,  and  a  dark  brown  liquor  is  formed. 
If  leather  made  by  my  process  is  put  in  a  strong  soda 
solution,  the  liquor  obtained  shows  only  a  little  milky 
colour. 

"  Leather  made  by  my  process  is  very  strong,  soft, 
elastic,  and  my  process  is  applicable  to  hides  or  skins 
of  every  description." 

It  is  obvious  that  many  improvements  in  the  manipula- 
tion of  the  above  process  have  been  introduced  since 
it  was  brought  out.  As  a  matter  of  fact,  however,  the 
main  principle  of  the  impregnation  of  the  skin  with 
chromic  acid  remains  much  the  same,  and  excellence  is 
obtained  by  a  variety  of  small  points  in  the  subsequent 
mechanical  manipulations,  mainly  by  the  employment 
of  ingenious  machinery  and  suitable  materials.  Theo- 
retically, chrome  leather  is  easy  to  make,  but  in  practice 
it  is  very  difficult  to  attain  any  great  amount  of  com- 
mercial success  without  a  large  expenditure,  enterprise, 
and  technical  knowledge. 

Chrome  leather  may  be  made  by  two  methods,  which 
are  technically  known  as  the  "  one- bath  "  and  the  "  two- 
bath  "  methods.  Opinions  differ  as  to  the  results  obtained 
by  each,  but,  generally  speaking,  the  heavier  leathers, 
such  as  harness,  belting,  picker,  and  calf  leathers,  are 
obtained  by  the  use  of  the  one-bath  method,  which  is 


CHROME  LEATHER  MANUFACTURE.  327 

very  simple  in  its  application,  and  depends  upon  the  use 
of  a  dilute  solution  of  a  basic  chromic  salt,  the  goods 
being  subjected  to  its  action  in  gradually  increasing 
strengths  until  struck  through.  This  method  will  be 
dealt  with  later  on. 

Light  goods,  however,  such  as  glazed  goat  and  sheep 
skins,  are  generally  treated  by  the  two-bath  process,  and 
the  following  summary  may  be  taken  as  fairly  repre- 
sentative of  the  method  now  in  vogue  :  — 

CHROME  OR  GLAC£  GOAT  SKINS. 

The  immense  demand  for  goat  skins  has  led  to  a  regular 
advance  in  the  price  of  the  raw  material,  and  it  has  been 
humorously  said  that  where  a  goat  is  wandering,  there 
waits  an  American  for  him  to  die.  It  will,  therefore,  be 
gathered  that  the  demand  for  skins  is  very  great,  so  much 
so  that  there  is  now  no  corner  of  the  world  which  has  not 
been  drawn  upon  for  supplies.  The  enhanced  value  of  the 
pelt,  too,  has  led  to  increased  attention  being  devoted  to 
its  primary  preparation  for  storage  and  transit,  and  skins 
are  now  carefully  treated  with  various  compounds  for  more 
complete  preservation.  A  large  business  has  sprung  up, 
for  instance,  with  Australia  and  New  Zealand  in  the 
export  of  what  are  known  as  pickled  skins.  These  are 
put  through  the  preparing  process  of  soaking,  liming,  and 
unhairing,  fleshing,  scudding,  &c.,  when  they  are  given  a 
bath  of  weak  sulphuric  acid  solution.  In  this  they  rapidly 
swell ;  salt  is  then  added,  and  the  skins  become  reduced, 
and  are  in  reality  pickled  with  a  sort  of  glauber  salt. 
The  result  is  fairly  good,  but  the  recent  Society  of  Arts 
committee,  appointed  to  deal  with  the  deterioration  of 
bookbinding  leather,  has  pointed  out  that  the  action  of 
the  acid  often  tends  to  a  serious  weakening  of  the  animal 
fibre,  and  that  the  resultant  leather  is  sometimes  not  to 
be  depended  upon.  The  result  has  been  that  other  pre- 
servative agents  have  been  employed,  such  as  formic 
and  acetic  acids,  and  it  is  claimed  their  use  shows  a 


328  LEATHER  MANUFACTURE. 

distinct  improvement  upon  the  ordinary  pickling  or 
salting  methods. 

Various  proprietary  articles  have  also  been  put  on 
the  market  for  the  purpose,  and  one  especially  has  given 
remarkably  good  results,  viz.  Atlas  Preservative  "  S,"  sold 
by  the  Atlas  Preservative  Company,  Windmill  Lane 
Wharf,  Deptford,  London,  S.E.  This,  it  is  claimed,  per- 
fectly preserves  skins  and  hides  in  a  fresh  condition,  and 
no  difference  can  be  detected  in  the  finished  leather  when 
compared  with  that  made  from  fresh-slaughtered  goods. 
This  preservative  may  be  used  with  a  little  salt  in  such  a 
manner  as  to  keep  the  skins  in  a  damp  and  moist  condi- 
tion, or  painted  in  a  weak  solution  on  the  flesh  side,  and 
the  skins  subsequently  dried  out  and  baled  for  transport. 
As  it  is  usual  to  find  about  ten  per  cent,  of  badly  damaged 
skins  in  certain  grades  of  goat  skins,  the  fact  that  a  method 
has  been  evolved  to  stop  this  economic  waste  cannot  be 
too  widely  known.  Experts  have  reported  very  favour- 
ably on  the  Atlas  Preservative,  and  good  leather  has 
been  made  from  skins  treated  in  all  parts  of  the  world. 

Preliminary  Operations. — A  good  deal,  of  course, 
depends  upon  the  sort  and  condition  of  the  various 
goat  skins,  as  regards  the  first  stages  of  glace  goat  manu- 
iacture.  Skins,  as  before  mentioned,  are  of  world-wide 
origin,  and  the  pelts  from  Southern  Europe,  South 
America,  China,  and  India  all  show  various  charac- 
teristics which  necessitate  differences  in  treatment.  The 
most  esteemed  skins  perhaps  are  what  are  known  as 
Patna  skins,  coming  from  India.  These,  generally 
speaking,  are  of  good  quality  and  fibre,  and  produce  a 
fine  and  close  grain,  which  is  a  sine  qua  non  in  kid 
manufacture.  Taking  this  class,  then,  as  representative, 
the  procedure  is  as  follows :  The  skins  are  first  soaked 
in  plenty  of  clean  water;  the  time  varies  according  to 
the  condition  of  the  skins,  but  about  two  or  three  days 
should  be  sufficient  to  bring  them  back  to  a  good  soft 
condition.  This  is  greatly  facilitated  by  the  addition  of 
a  little  borax  or  soda  to  the  soak  liquors,  about  one  pound 
of  borax  per  three  hundred  gallons  being  considered 


CHROME  LEATHER  MANUFACTURE.  329 

sufficient  for  the  purpose.  Sulphide  of  sodium  is  also 
used  for  the  same  purpose,  and  has  a  decided  effect 
on  softening  the  hard  nature  of  the  skins  and  getting 
them  into  condition  for  liming.  Care  should,  of  course, 
be  taken  that  putrefaction  does  not  set  in,  and  this  may 
be  guarded  against  by  changing  the  first  water  after 
about  twenty-four  hours,  and  after  drawing  the  skins, 
to  put  them  into  the  second  soak  treated  with  some 
disinfectant. 

If  the  skins  are  very  hard  and  dirty,  a  "breaking 
over  "  between  the  changes  of  water  is  beneficial.  This 
breaking  over  is  done  in  small  tanneries  by  well  stretching 
and  working  the  wet  skin  with  a  blunt  tanner's  knife  over 
the  half-round  beam.  In  the  large  chrome  works,  how- 
ever, this  mechanical  softening  is  at  times  done  by  the  use 
of  the  fulling  stocks  (see  Fig.  6).  The  pounding  motion  of 
this  machine  is  very  effective  where  short-haired  skins 
are  under  manipulation,  and  from  twenty  minutes  to 
half  an  hour  is  usually  ample  time  to  break  down  the 
most  obstinate  pelt.  Some  classes  of  skins  may  be 
softened  effectually  in  a  drum  tumbler;  but  however 
softened,  the  general  theory  should  be  to  bring  the  pelts 
back  as  far  as  possible  to  their  original  soft  and  pliant 
condition. 

Liming  and  Unhairing. — In  the  manufacture  of  glace 
goat,  lime  and  arsenic  sulphide  are  the  materials  gener- 
ally favoured  for  depilation.  Experience  has  shown  that 
the  action  of  lime  loosens  the  hair,  distends  the  fibres  of 
the  skin,  assists  to  neutralize  the  natural  fat,  and  so  far  acts 
upon  other  constituents  not  necessary  to  leather-making 
that  they  may  be  mechanically  worked  out  later.  In 
practice  it  is  common  to  add  about  5  Ibs.  of  "red 
arsenic  "  to  about  100  Ibs.  of  lime  slacked  in  a  large  tub. 
The  lime  should  be  thoroughly  slaked  with  enough  water 
to  moisten  it,  and  the  arsenic  added  and  mixed  thoroughly 
with  the  lime,  and  the  whole  mass  well  stirred.  A  minor 
objection  is  that  sulphuretted  hydrogen  is  evolved  during 
the  process,  so  that  it  should  be  carried  out  in  the  open 
air,  if  possible.  The  arsenic  helps  to  shorten  the  time  of 


330  LEATHER  MANUFACTURE. 

the  depilating  process,  whilst  it  also  greatly  assists  in 
producing  leather  of  a  supple  texture  and  a  smooth 
grain. 

When  the  above  quantities  of  lime  and  arsenic  are 
dissolved  the  solution  is  thrown  into  the  pit  with  sufficient 
water,  care  being  taken  that  no  undissolved  particles  or 
stones  find  their  way  in.  No  definite  rule  can  be  laid 
down,  but  the  quantities  stated  are  sufficient  to  unhair 
from  five  hundred  to  six  hundred  skins.  After  the  skins 
have  laid  in  the  solution  for  a  day  or  so  they  are  hauled 
up  and  laid  up  to  drain,  the  solution  being  well  plunged 
up  before  the  skins  are  re-entered.  It  may  be  also 
necessary  to  strengthen  it  by  the  addition  of  a  little  more 
lime  and  arsenic  after  a  day  or  two,  but  a  good  deal 
depends  upon  whether  old  or  new  liquors  were  used  at 
the  start ;  generally  speaking,  it  is  inadvisable  to  use 
much  lime  toward  the  end  of  the  process,  as  it  has  a 
tendency  to  produce  a  coarse  grain  on  the  finished  leather. 
In  some  factories  it  is  considered  safe  to  start  with  a  liquor 
showing  about  3°  Twaddle,  and  finishing  up  with  one  at 
about  5°  or  6°.  The  time  taken  for  depilation  varies,  but 
may  be  approximately  put  at  from  ten  to  fourteen  days,  a 
good  deal  depending  upon  the  condition  of  the  skins,  the 
temperature  of  the  solution,  and  the  handling  the  goods 
receive.  Some  manufacturers  profess  to  have  had  good 
results  in  the  use  of  sulphide  of  sodium  for  unhairing. 
This  has  the  disadvantage  of  practically  destroying  the 
hair,  and  as  this  in  some  classes  of  goat  skins  is  valuable, 
the  sulphide  is  not  much  favoured  for  that  reason.  Various 
methods  are  followed  out  where  sulphide  is  used  ;  it  may 
be  painted  on  the  flesh  side  of  the  skins,  or  the  skins 
may  be  thrown  into  a  weak  solution ;  or,  again,  it  may  be 
used  in  conjunction  with  lime  as  in  the  case  of  arsenic 
sulphide.  However,  as  practically  all  the  successful 
chrome  goat  manufacturers  use  the  arsenic  limes,  it  is 
not  perhaps  advisable  to  take  up  valuable  space  by  deal- 
ing further  with  the  sulphide  of  sodium  methods.  If 
sulphide  of  sodium  is  used  in  conjunction  with  lime, 
about  a  third  of  the  former  is  sufficient ;  the  goods  are 


CHROME  LEATHER  MANUFACTURE.  331 

worked  much  as  in  the  case  of  lime,  and  the  skins  are 
ready  for  unhairing  in  about  six  to  ten  days,  according  to 
substance,  &c.  When  the  skins  have  had  enough  lime  they 
are  usually  washed  in  water  tocleanse  themas  faras  possible, 
and  if  the  shanks,  &c.,  have  not  been  removed  before,  they 
are  trimmed  away  when  the  skins  are  ready  for  unhairing. 

The  unhairing,  being  a  very  simple  operation,  is  often 
done  by  hand  on  the  half-round  tanner's  beam  with  a 
blunt  knife ;  of  late  years,  however,  this  operation  1ms 
been  done  by  machine.  The  only  drawback  to  the  use 
of  the  machine  for  unhairing  is  that  the  holey  and  de- 
fective skins  are  rather  harshly  treated,  and  if  great  care 
is  not  used  a  skin  is  often  so  torn  by  the  action  of  the 
spiral  knives  that  it  is  practically  worthless. 

Fleshing. — In  nearly  all  large  chrome  leather  works 
goat  skins  are  fleshed  by  machine.  The  operation  is, 
however,  comparatively  simple,  and  in  countries  where 
there  is  an  abundant  supply  of  cheap  labour,  it  is  easy  to 
train  men  to  flesh  goat  skins  in  the  old-fashioned  way  with 
the  ordinary  tanner's  knife.  Goat  skins,  as  a  rule,  are  not 
very  fleshy,  and  most  of  the  loose  tissue  can  be  removed 
by  the  "  brushing "  or  scraping  edge.  The  machine 
usually  employed  for  fleshing  is  illustrated  at  Fig.  74, 
the  skin  being  spread  flesh  outwards  on  a  special  rubber 
roller,  and  subjected  to  the  action  of  a  cylinder  fitted 
with  spiral  knives.  A  modified  form  of  the  machine, 
shown  as  Fig.  64,  is  also  olten  used  for  fleshing.  The 
work  done  by  the  machine  answers  on  the  whole  very 
well,  and  is  cheaper  in  Europe  and  America  than  the 
hand  process  could  be.  Many  small  glazed  kid  manu- 
facturers use  the  same  machines  for  unhairing,  fleshing, 
and  scudding,  using  different  cylinders  for  the  various 
purpose*.  As  the  output  of  chrome  kid,  however,  has 
to  be  very  large  to  ensure  a  profit,  this  is  not  to  be 
recommended,  except  for  exceptional  cases,  or  for  the 
experimental  stage  of  glazed  kid  manufacture.  In 
machine  fleshing  great  attention  should  be  paid  to  the 
cutting  cylinder  and  to  the  rubber  bolster,  otherwise  the 
work  will  be  defective,  and  a  good  deal  of  damage  ensue 


332  LEATHER  MANUFACTURE. 

to  the  skins  under  operation.  In  no  case  should  fleshing 
be  entrusted  to  any  but  a  most  intelligent  man,  who 
should  be  encouraged  by  good  wages  to  become  a 
thorough  master  of  the  operation. 

Puring  or  De-liming. — To  ensure  the  production  of  a 
good  tough  and  elastic  leather  with  a  fine  "  break  "  and 
grain,  it  is  necessary  to  pay  special  attention  to  this 
process.  If  lime  be  present  in  the  skins  when  they  go  to 
the  chrome  bath,  it  is  turned  into  sulphate  of  lime,  and 
the  leather  is  hard  and  often  brittle.  After  fleshing,  the 
skins  are  trimmed  where  necessary,  and  well  washed  in 
plenty  of  soft  water  to  remove  as  much  lime  as  possible, 
and,  after  draining,  are  ready  for  the  puring  operation. 
All  sorts  of  de-liming  agents  have  been  tried,  such  as 
sulphuric  and  lactic  acids,  &c.,  but  experience  has  shown 
that  in  the  majority  of  cases  the  old  and  disagreeable 
excrement  pure  gives  the  best  results.  Some  manu- 
facturers, however,  claim  to  have  used  "  Erodin,"  intro- 
duced by  Mr.  J.  T.  Wood,  of  Nottingham,  and  Drs.  Popp 
and  Becker,  of  Germany,  with  good  results.  This  bate, 
or  pure,  depends  for  its  effect  upon  the  bacteriological 
action,  and  was  invented  after  much  patient  experiment- 
ing had  enabled  the  inventors  to  isolate  the  active 
organism,  and  to  put  a  culture  and  a  cheap  medium  for 
its  propagation  before  the  trade. 

Space,  however,  will  not  admit  of  enlarging  upon  the 
various  de-liming  agents  which  have  been  tried,  and  as 
dog-dung  is  by  many  still  regarded  as  the  best  material 
for  glace  goat,  we  will  devote  our  limited  space  to  a  con- 
sideration of  its  use.  In  puring  it  is  necessary  to 
remove  the  dissolved  gelatinous  substance,  the  hair 
sheaths,  fat  glands,  &c.,  and  the  lime  soap  produced 
by  the  action  of  the  lime  on  the  natural  fat  of  the  skin. 

For  the  heavier  kinds  of  hides  and  skins,  hen  and 
pigeon  dung  is  used  for  bateing,  but  in  England  dog- 
dung  is  almost  exclusively  employed  for  the  process  in 
goat-leather  manufacture.  It  is  usually  obtained  from 
dog-kennels,  and  as  it  varies  in  strength  and  charac- 
teristics, it  is  difficult  to  give  any  definite  directions  for 


CHROME  LEATHER  MANUFACTURE.  333 

its  use.  As  dog-dung  rapidly  ferments  it  should  not  be 
exposed  much  to  the  air.  In  many  works  it  is  mixed 
with  a  little  water  to  a  paste,  and  kept  in  this  way,  and 
in  no  case  should  the  dung  be  used  until  it  has  been 
allowed  to  ferment  for  six  or  seven  days.  In  practice  a 
few  pails  of  the  semi-liquid  dung  is  added  to  water  at  a 
temperature  of  about  90°  Fahr.,  the  dung  being  first 
strained  through  a  coarse  bag  to  remove  bits  of  bone, 
gravel,  and  other  sediment.  The  skins  soon  begin  to 
"  fall "  in  the  solution,  or  lose  their  plumpness,  and  are 
considered  to  be  sufficiently  pured  when  the  grain 
retains  the  impression  of  the  thumb  or  fingers.  In  large 
works  this  puring  operation  is  performed  in  paddles, 
the  strength  of  the  concoction  and  the  time  the  skins 
are  allowed  to  remain  in  it  varying  according  to  the 
system  followed  out  or  the  ideas  of  the  pureman,  who, 
by  the  way,  should  be  an  experienced  and  skilled 
workman. 

Scudding. — After  the  skins  have  been  pured,  drenched, 
or  both,  as  the  case  may  be,  they  are  then  carefully 
worked  over  on  the  grain  side  to  remove  the  lime-soap, 
pigment,  fat,  short  hairs,  and  other  matter.  This  is  also 
a  very  necessary  operation,  as  if  much  "  scud  "  is  left  in 
the  skins,  the  leather  on  finishing  refuses  to  glaze  pro- 
perly, whilst  any  hairs  remaining  would  quite  spoil  the 
look  of  the  finished  article. 

In  some  places  the  scudding  is  still  done  on  the 
tanner's  beam  with  the  half-round  slate  "  knife,"  the 
workman  thoroughly  extending  and  working  out  the  soft 
and  flaccid  skin  in  every  direction.  It  is  usual  now, 
however,  to  do  this  operation  by  a  machine  similar  to 
that  described  in  fleshing,  the  skin  being  subjected  to 
the  action  of  a  cylinder  into  which  slate  tools  are  let 
in,  the  bolster  being  of  stout  rubber.  The  work  is  done 
fairly  well  and  very  cheaply ;  but  it  is  a  good  rule  to 
have  the  skins  examined  and  to  rectify  any  faults  by  hand 
on  the  beam.  Some  of  the  short-haired  goat  skins,  such 
as  Patnas,  often  scud  very  badly,  and  want  a  good  deal 
of  attention  to  get  a  clean  and  fine  grain.  Others,  again, 


334  LEATHER  MANUFACTURE. 

such  as  Chinese  skins,  scud  well  and  make  good  clean 
leather  with  comparatively  little  trouble. 

Too  much  attention  can  hardly  be  paid  to  this  branch 
of  glace  leather  manufacture,  and  attempts  at  economy 
here  may  turn  out  disastrously  later  on  if  the  pelts  are 
not  freed  from  impurities  and  short  hair.  It  is  even 
necessary,  in  extreme  cases,  to  lightly  shave  the  grain 
where  the  liming  or  puring  operations  have  not  been 
carried  out  thoroughly.  After  scudding,  the  skins  are 
either  left  for  a  few  hours  to  drain,  or,  if  necessary,  are 
washed  in  plenty  of  clean  water.  Some  manufacturers 
wash  in  the  paddle  in  a  dilute  lactic  acid  solution,  and 
then  in  a  weak  borax  solution,  1  Ib.  of  the  latter  to  about 
150  to  200  gallons  of  water  being  sufficient. 

Chroming  Operations. — No  two  glace  goat  makers 
follow  quite  the  same  procedure,  and  whilst  some  see  an 
advantage  in  giving  the  skins  a  pickle  of  acid  and  salt 
before  proceeding  to  the  actual  chrome  tanning,  others 
dispense  with  this  process  as  unnecessary.  If  the  former 
process  is  done,  however,  one  American  authority  says 
that  10  Ibs.  of  salt  for  each  100  Ibs.  of  drained  pelt,  dis- 
solved in  15  gallons  of  water,  is  sufficient.  The  skins  are 
run  in  a  drum  with  this  solution  for  about  fifteen 
minutes,  and  the  acid  given.  This  is  prepared  by  mixing 
2  Ibs.  of  muriatic  acid  (hydrochloric)  in  a  pail  of  boiling 
water  and  cooled  with  two  pails  of  cold  water.  This 
is  added  to  the  skins  in  the  drum,  which  are  run  for 
another  fifteen  minutes,  when  the  skins  are  ready  for  the 
chrome  bath. 

The  saturation  of  the  lighter  pelts,  such  as  calf  and 
goat,  with  the  chromic  acid  is  invariably  carried  out  in 
the  paddle  or  drum,  and  in  all  large  works  separate  ones 
are  used  for  tanning,  reducing,  washing,  &c.  Care  should 
be  taken  to  see  that  the  driving  arrangements  are  always 
in  good  order,  as  a  breakdown  often  involves  serious 
trouble  and  loss. 

The  chrome  bath  is  prepared  by  dissolving  bichromate 
of  potash  in  boiling  water  which  is  acidified  with 
hydrochloric  acid,  and  this  is  added  to  the  goods 


CHROME  LEATHER  MANUFACTURE.  335 

whilst  they  are  running  in  a  suitable  quantity  of  water. 
The  quantity  of  bichromate  of  potash  is  calculated  on 
the  weight  of  the  wet  drained  skins,  and  varies  from 
4  to  G  Ibs.  per  cent.  In  practice,  about  15  gallons 
of  water  to  100  Ibs.  of  skins  is  recommended.  The 
amount  of  bichromate  of  potash  is  not  very  material, 
but  from  5  to  6  Ibs.  per  cent,  of  wet  pelt  is  a  safe  margin. 
One  method  is  to  dissolve  6  Ibs.  of  bichromate  of  potash 
in  20  gallons  of  water,  to  which  is  carefully  added  o  Ibs. 
of  acid.  Some  authorities  also  advise  the  addition  of  a 
few  pounds  of  salt  to  the  solution,  but  of  this  the  writer 
has  had  no  experience.  In  practice  it  is  advisable  to 
dissolve  the  bichromate  of  potash  in  a  suitable  quantity 
of  hot  water,  and  add  the  solution  to  the  goods  whilst  in 
motion  in  the  drum  or  paddle,  the  requisite  amount  of 
acid  being  added  in  successive  stages. 

The  skins  are  padded  in  the  acidified  liquor  until  they 
assume  a  yellow  colour  throughout,  the  process  being 
finished  when  a  cut  in  the  thickest  part  of  the  skin  shows 
complete  penetration.  When  completely  struck  through, 
the  skins  are  taken  out  of  the  acid  solution,  horsed  up 
carefully,  care  being  taken  to  avoid  light  and  wrinkles, 
and  the  excess  of  liquor  struck  out  by  machine.  The 
next  process,  technically  called  "  reducing,"  is  the  re- 
duction of  the  chromic  acid.  In  many  works  the  skins 
are  first  dipped  one  by  one  into  a  weak  solution  composed 
of  about  4  or  5  Ibs.  of  hyposulphite  of  soda  dissolved  in 
15  gallons  of  water;  this  is  sufficient  for  100  Ibs.  of  wet 
pelt.  This  dipping  process  is  assumed  to  somewhat  "  set " 
the  grain  side  of  the  leather,  and  so  prevent  the  tendency 
of  wrinkling  or  coarseness  caused  by  the  sharp  action  of 
the  reducing  bath.  This  latter  is  usually  done  in  paddles, 
10  Ibs.  of  hyposulphite  of  soda  being  dissolved  in  20 
gallons  of  water  and  added  to  the  proper  amount  of 
water  in  the  paddle.  Five  per  cent,  of  muriatic  acid, 
calculated  on  the  wet  weight  of  the  skins,  is  then  added, 
and  the  skins  paddled  in  this  until  they  lose  their  original 
yellow  colour  and  assume  a  bluish-green  tint  through- 
out. It  is  a  good  plan  in  practice  to  so  arrange  the 


336  LEATHER  MANUFACTURE. 

work  that  the  chroming  begins  in  the  morning  and  is 
completed  in  the  evening.  It  is  of  the  greatest  im- 
portance that  the  reduction  should  be  complete,  as  no 
amount  of  work  in  the  subsequent  stages  will  ever  make 
a  first-rate  article.  It  is  also  an  advantage  if  the  skins 
are  sorted  into  various  substances  before  chroming,  other- 
wise the  penetration  is  uneven  throughout  the  pack,  and 
the  heavy  skins  may  be  under-tanned.  It  might  also  be 
mentioned  that  the  reduction  should  be  done  in  a  well- 
ventilated  room,  as  the  fumes  given  off  during  the 
process  are  both  disagreeable  and  detrimental  to  the 
health  of  the  workman.  When  the  skins  are  perfectly 
chromed  throughout  they  are  taken  out  of  the  paddle, 
and  are  then  given  a  prolonged  washing  in  a  weak  borax 
solution,  followed  by  plenty  of  water.  This  will  neutra- 
lise any  free  acid  remaining,  and  should  be  continued 
until  no  reaction  is  shown  by  the  leather  when  tested  with 
litmus  paper. 

Striking-out  and  Shaving. — The  skins  are  next  well 
struck  out  by  machine,  and  passed  on  to  the  shaving 
machine.  In  the  case  of  goat  skins  it  is  often  only 
necessary  to  level  the  necks  and  backs  of  the  skins, 
although  if  of  stout  substance  they  will  require  reducing 
all  over.  This  process  must  be  done  with  judgment  and 
by  careful  operators,  if  damage  to  the  leather  is  to  be 
avoided.  The  fact,  too,  that  there  is  a  certain  element 
of  danger  in  working  the  shaving  machine  should 
make  the  selection  of  operators  worthy  of  more  than 
ordinary  consideration.  The  cost  of  machine  shaving  is 
not  great,  and  varies  from  about  a  penny  to  threepence 
per  dozen. 

Dyeing  Chrome  Leather. — If  the  skins  are  to  be 
divided  into  black  and  coloured  work,  the  sorting  must 
be  done  at  this  stage ;  only  the  finest  and  most  perfect 
grain  skins  are  suitable  for  colouring  fancy  shades,  so 
that  those  which  are  marked,  imperfect  on  the  grain,  or 
greasy,  should  be  put  for  black  work.  At  the  same 
time  it  must  be  remembered  that  the  quality  of  the 
black  skins  is  obviously  deteriorated  by  sorting  the 


CHROME  LEATHER  MANUFACTURE.  337 

best  skins  out,  so  that  a  good  deal  of  judgment  is 
required. 

Dealing  with  the  black  skins,  the  first  operation  is  to 
mordant  them  for  dyeing.  This  is  technically  termed 
"  blue-backing,"  as  it  has  the  effect  of  colouring  the  flesh 
side  of  the  skins  a  sort  of  bluish  purple.  The  usual  method 
is  to  immerse  the  skin  in  a  solution  of  warm  logwood  for 
about  half  an  hour,  using  the  paddle  or  tumbler  for  the 
purpose.  Hemolin  is  also  used  for  the  same  purpose,  but 
it  is  said  the  skins  lose  a  slight  fullness  imparted  to  them 
by  the  more  astringent  logwood.  An  American  authority 
says  the  following  method  of  dyeing  black  produces  a 
very  satisfactory  result.  The  skins  are  drummed  in  a 
liquor  made  up  of  about  4  ozs.  of  liquid  sumac  extract  in 
5  gallons  of  warm  water,  this  being  the  quantity  required 
for  about  a  dozen  skins.  The  skins  are  then  dyed  with  a 
purple  aniline,  about  3  ozs.  being  sufficient  for  a  dozen 
skins.  The  skins  are  then  passed  through  logwood  or 
hemolin  liquor,  and  then  through  the  iron  striker,  and 
finished  off  with  a  bath  of  aniline  black  at  a  temperature 
of  about  130°  Fahr.  Nigrosine,  methyl  violet,  and 
other  anilines  are  also  used  for  blue-backing,  but  in 
many  cases  glace  leather  manufacturers  prefer  to  depend 
mainly  upon  the  use  of  the  logwood  solution,  assisted  by 
hemolin,  &c.,  which  they  consider  give  the  best  results 
generally. 

Fat-Liquoring. — When  the  skins  are  blue-backed 
they  are  then  ready  for  the  next  operation,  termed  "  fat- 
liquoring."  This  is  necessary  for  the  thorough  lubrica- 
tion of  the  fibres,  and  to  produce  a  supple  and  tough 
leather. 

Experience  has  shown  that  the  most  convenient  time 
for  the  process  is  after  the  logwood  mordanting  bath, 
although  the  process  is  sometimes  done  after  the  final 
dyeing.  Broadly  speaking,  the  fat-liquor  is  simply  an 
emulsion  in  water  of  some  oily  or  fatty  material,  or 
materials.  Most  leather  manufacturers  have  their  own 
special  mixture.  Xeatsfoot  oil,  egg  yolk,  olive  and 
castor  oils,  special  soaps,  also  sod  oil  and  degras,  are  all 


338  LEATHER  MANUFACTURE. 

used,  but  the  first  two  named  materials  are  perhaps  the 
best  for  kid  leather,  which  has  to  bear  a  high  polish  and 
a  perfectly  clear  surface.  Turkey  red  oil  has  also  been 
recommended  for  the  purpose.  Professor  H.  K.  Procter 
states  that  Turkey  red  oil  (which  is  sulphated  castor  oil) 
makes  a  convenient  fat-liquor  mixed  with  warm  water 
without  soap,  and  has  been  advocated  where  delicate 
colours  are  to  be  dyed  after  fat-liquoring,  although  it 
is  said  to  tend  toward  making  the  leather  tender  and 
hard. 

Fat-liquors  should  be  as  nearly  neutral  as  possible, 
although  if  any  acid  has  been  left  in  the  skins  a  neutral 
fat-liquor  will  cause  a  deposit  of  gummy  matter  on  the 
grain  almost  impossible  to  get  rid  of.  Procter  gives  1J 
per  cent,  of  castor  oil  soap  and  f  per  cent,  of  castor 
or  olive  oil  on  the  wet  weight  of  the  pelt  as  being 
serviceable.  Another  fat-liquor  which  is  claimed  by 
an  American  writer  to  give  great  softness  to  the  skins 
is  made  as  follows:  20  Ibs.  of  soft  soap  and  40  Ibs.  of 
sod  oil  is  thoroughly  emulsified  in  50  gallons  of  water. 
The  soap  should  first  be  boiled  in  a  few  gallons  of  water, 
and  the  oil  added,  and  enough  water  then  added  to  make 
up  the  50  gallons.  About  2  gallons  of  this  fat-liquor  per 
dozen  is  sufficient,  and  the  liquor  should  be  used  in  the 
drum  at  a  temperature  of  130°  to  160°  Fahr. 

For  fine  glazed  kid  the  writer  has  always  obtained 
good  results  with  suitable  soap,  neatsfoot  oil,  and  egg 
yolk  for  the  fat-liquor,  which  is  safe  and  easy  to  prepare. 
Fifty  gallons  of  this  may  be  prepared  by  cutting  up 
10  Ibs.  of  good  soap  and  boiling  in  50  gallons  of  water, 
adding  3  or  4  gallons  of  best  neatsfoot  oil  by  instalments 
until  thorough  emulsification  takes  place.  It  is  con- 
venient in  practice  to  use  only  a  part  of  the  50  gallons 
for  emulsifying,  and  to  add  the  remainder  cold,  or  nearly 
so,  to  bring  down  the  temperature  to  about  90°  Fahr. 
before  adding  the  egg  yolk  ;  otherwise  the  latter  will  be- 
come more  or  less  insoluble.  Two  or  three  gallons  of  this 
fat-liquor  per  dozen  is  sufficient,  although  it  is  obvious  a 
good  deal  will  depend  upon  the  condition  and  size  of  the 


CHROME  LEATHER  MANUFACTURE.  339 

skins.  If  any  trouble  is  found  in  emulsifying,  a  little 
borax  added  to  the  boiling  liquor  is  usually  beneficial. 

Skins  should  be  allowed  to  drain  before  fat-liquoring, 
arid  the  fat-liquor  added  to  the  goods  quickly  whilst  the 
drum  is  in  motion.  About  half  an  hour  is  sufficient  for 
the  leather  to  absorb  the  fatty  matters,  and  a  little 
experience  in  handling  the  skins  will  soon  indicate  the 
proper  time  and  quantities  required. 

At  the  completion  of  this  process  the  skins  are  care- 
fully folded  grain  out  straight  down  the  back,  and 
allowed  to  lay  on  a  suitable  horse  for  a  day,  or  more, 
to  enable  the  fibres  of  the  leather  to  have  the  full  benefit 
of  impregnation  with  the  greasy  matters. 

Dyeing  Black. — After  the  fat-liquoring  operation  the 
skins  are  then  ready  for  dyeing  black.  This  may  be  done 
either  by  brushing  them  with  the  "  striker  "  on  the  table, 
or  by  passing  the  skins  through  the  logwood  and  iron  so- 
lution in  suitable  vats  or  trays.  Some  manufacturers  have 
also  tried  dyeing  chrome  goat  in  the  drum,  but  the  writer 
prefers  the  tray  method  for  several  reasons,  which  would 
take  up  too  much  space  here  for  discussion.  The  dyeing 
liquor  varies  somewhat  in  composition,  but  the  following 
is  a  safe  formula  for  a  black  striker  :  Dissolve,  by  boiling 
in  40  gallons  of  water,  5  Ibs.  of  copperas  and  about 
24  ozs.  of  blue  vitriol,  adding  1  Ib.  of  ground  nut-galls. 
The  skins  are  first  folded  down  the  centre  grain  out,  and 
perhaps  slicked  down  with  a  smooth  glass  to  protect  the 
flesh  side  as  much  as  possible,  and  are  then  passed  in 
small  packs  through  a  strong  logwood  liquor,  which  is 
all  the  better  if  boiled  with  a  little  fustic  wood.  After 
this  they  are  worked  through  the  striker  in  a  dilute  form 
until  a  deep  black  is  obtained.  As  the  iron  striker  is 
rather  inclined  to  roughen  the  grain  if  used  too  strong, 
care  must  be  taken  to  guard  against  this.  It  is  more 
difficult  to  obtain  a  good  chrome  black  than  would  be 
supposed,  and  the  dyeing  should  be  executed  in  a  light 
part  of  the  works,  and  entrusted  to  the  care  of  one 
who  has  had  some  experience  in  the  matter,  otherwise 
"  bronzing  "  or  an  ugly- looking  grey  will  be  the  result. 


340  LEATHER  MANUFACTURE. 

After  the  skins  are  dyed  a  fine  deep  black  they  are  well 
rinsed  through  a  tub  of  cold  water,  horsed  up,  and 
allowed  to  drain. 

An  American  authority  gives  the  following  method  of 
combining  fat-liquoring  and  black  dyeing  in  the  drum. 
The  black  is  composed  of  warm  logwood  liquor,  in  which 
5  Ibs.  of  gum  arabic  are  dissolved,  whilst  8  Ibs.  of 
copperas  are  dissolved  in  another  vessel.  The  gum  and 
copperas  solution  are  then  mixed  with  25  gallons  of 
strong  logwood  liquor.  When  the  skins  have  received 
the  fat-liquor  the  black  liquor  is  added  to  the  skins 
whilst  the  drum  is  in  motion,  which  is  then  run  for 
another  five  minutes  ;  the  skins  are  then  washed  in  cold 
water  and  struck  out  in  the  ordinary  way. 

Putting  or  Striking  Out. — At  this  stage  the  skins 
are  put  out  or  extended  by  machine,  the  machine  shown 
on  Fig.  73,  with  the  vertical  rising  table,  being  the 
most  suitable.  During  the  last  year  or  two,  however,  a 
new  machine  has  been  on  the  market  for  the  purpose, 
for  which  a  much  greater  output  of  work  is  claimed. 
This  consists  of  an  arrangement  by  which  four  tables 
are  kept  in  motion  on  the  one  machine,  and  under  certain 
conditions  it  answers  well,  although  some  users  allege 
there  is  hardly  time  for  proper  spreading,  feeding,  and 
taking  off  the  skins. 

The  skins  should  at  this  stage  be  struck  out  moder- 
ately tight  and  laid  out  flat,  grain  side  up,  when  they  are 
given  a  light  coat  of  equal  parts  of  glycerine  and  water, 
spread  on  with  a  suitable  wad  of  some  soft  material  or  a 
sponge. 

In  this  condition  the  skins  remain  for  a  few  hours,  and 
are  then  reset  or  again  struck  out.  This  time  they 
should  be  well  extended,  and  all  rough  and  uneven 
grain  removed  if  the  final  surface  is  to  be  smooth  and 
tine. 

Oiling  and  Drying. — The  struck-out  skins  are  then 
taken  to  a  warm  room  for  preference,  and  a  coat  of  oil 
applied  to  the  grain  side.  This  should  be  of  the  best 
quality,  and  if  reliable  neatsfoot  is  to  be  had  it  is,  perhaps, 


CHROME  LEATHER  MANUFACTURE.  341 

the  best  all-round  oil  for  the  purpose.  There  are,  of 
course,  other  good  oils  on  the  market,  but  the  damage 
likely  to  be  caused  in  the  leather  by  unsuitable  oil  is  so 
great  that  any  new  oil  should  be  at  first  experimented 
with  only  on  a  very  small  scale. 

The  oiled  skins  are  next  dried  out  in  a  heated  chamber. 
Opinions  differ  as  to  the  efficacy  of  sharp  drying,  but  the 
belief  is  common  that  the  quicker  the  drying  the  less 
likelihood  the  oil  has  of  either  setting  on  the  grain  side, 
or  of  "spueing"  up  to  the  surface  on  the  finishing  stages, 
or  even  in  the  finished  condition.  As  a  matter  of  fact,  the 
amount  of  drying  room  required  is  so  great  in  a  glazed 
leather  works  of  any  size  that  it  is  impossible  to  find  space 
enough  to  dry  slowly,  although  it  is  always  a  good  plan 
to  allow  the  drying  chamber  to  cool  down  before  the 
goods  are  taken  out.  The  method  usually  followed  is 
to  stretch  the  skins  out  by  the  hind  shanks  on  parallel 
racks  studded  with  sharp  tenter-hooks.  The  work  should 
be  so  arranged  that  the  skins  are  left  to  dry  during  the 
night,  and  taken  down  in  the  morning,  when  they  are 
comparatively  cool.  In  this  condition  the  skins  may  be 
stored  for  some  time,  and  should  improve  with  age, 
although  this  ageing  process  is  not  as  necessary  as  is  the 
case  with  alum-tanned  leathers,  which  used  often  to  be 
kept  for  six  months  before  finishing. 

GLAZED  KID  FINISHING. 

Staking  or  Softening — The  first  operation  in  the 
finishing  of  glace  kid  is  to  well  soften  the  leather ;  the 
process  is  known  as  staking,  and  is  now  almost  always 
done  by  machine  (see  Fig.  75).  The  name  of  the  pro- 
cess is  derived  from  the  fact  that  formerly  it  was  done  by 
pulling  the  skin  over  an  upright  wooden  stake,  into 
which  was  fixed  a  fairly  sharp  metal  plate.  In  the  early 
days  of  glace  leather  making  the  workman  used  his  knee 
as  well  as  his  hands  for  the  purpose,  the  operation  being 
known  as  knee-staking. 

To  bring  the  skins  into  the  right  condition  for  staking, 
they  are  covered  for  a  few  hours  with  damp  sawdust  and 


342  LEATHER  MANUFACTURE 

are  then  taken  to  the  machine  The  principle  of  the 
staking  machine  is  simple,  the  leather  being  extended 
and  worked  by  a  blunt  knife,  the  jaws  of  the  machine 
opening  and  closing  by  an  ingenious  mechanical  arrange- 
ment. The  work  is,  however,  rather  tiring,  as  the  pull  of 
the  staking  knife  has  to  be  neutralized  by  the  pressure  cf 
the  operator's  body.  Goat  skins  are  usually  staked 
twice,  once  from  neck  to  tail,  and  once  "  to  the  breath." 
Care  should  be  taken  to  see  the  shanks  are  opened  out  and 
a  good  pattern  given  to  the  skin.  Some  tanners  still 
have  their  skins  knee-staked  after  one  machining,  whilst 
others  have  them  sorted  over,  and  any  which  seem  at  all 
hard,  worked  over  with  a  moon-knife  or  arm-stake.  The 
cost  of  hand  work,  however,  is  so  great,  that  only  in  few 
instances  is  it  followed  out,  and  it  will  probably  soon 
disappear  altogether.  If  the  skins  are  very  fleshy  after 
staking  they  should  be  lightly  fluffed  on  a  wheel  covered 
with  fine  emery  powder,  but  as  a  rule  a  good  stiff  brushing 
on  the  flesh  is  sufficient  before  they  are  passed  on  for 
trimming.  This  consists  of  removing  the  edge  rags  of 
the  skins  with  a  pair  of  strong  shears,  and  is  quickly  and 
cheaply  done  by  girls  or  wromen. 

Seasoning. — The  softened  and  trimmed  skins  are  then 
prepared  for  glazing  by  being  wiped  over  on  the  grain 
side  with  a  mixture  known  as  a  "  season."  This  usually 
consists  of  blood  or  albumen  solution,  to  which  is  added 
colouring  matter  in  the  shape  of  logwood  decoction,  ink,  or 
black  aniline  dye.  It  is  a  mistake  to  give  the  leather  too 
much  seasoning ;  the  idea  should  be  simply  to  bring  the 
leather  into  condition  for  the  subsequent  glazing  process. 
Many  seasons  are  sold  ready  prepared  ;  but  for  the  benefit 
of  those  who  prefer  to  make  their  own,  the  following  will 
be  found  useful : — 

6  qts.  logwood  liquor ; 

2    „    ox  blood ; 

J  pt.  orchil ; 

2  pts.  water ; 

£    „    ammonia; 
milk. 


CHROME  LEATHER  MANUFACTURE.  343 

Another — 

5  gals,  logwood  liquor ; 
5  ozs.  copperas ; 
\\  pts.  blood; 
5  ozs.  glycerine ; 
8    „  ammonia. 

In  many  factories  girls  are  employed  for  the  seasoning, 
and  their  nimbleness  and  lightness  of  touch  makes  them 
very  suitable  for  the  work.  In  summer  time  the  addition 
of  some  cheap  antiseptic,  such  as  phenol  (carbolic  acid), 
will  keep  the  seasoning  from  becoming  offensive.  The 
season  should  be  spread  evenly  and  lightly  with  a  soft 
pad  and  the  skins  hung  up  to  dry. 

Glazing — This  being  practically  the  last  operation  care 
must  be  taken  to  render  it  effective.  Glace  goat  glazing 
may  be  called  a  skilled  business  :  in  any  event,  the  pro- 
portion of  bad  work  makes  it  an  expensive  matter  to  teach 
operatives  the  process,  and  none  but  those  of  a  high  order 
of  intelligence  should  be  employed. 

A  good  deal  depends  upon  the  machine  used  for 
the  purpose,  and  the  one  in  general  use  is  known  as 
the  "  Bower."  This  is  built  almost  entirely  of  wood,  the 
pressure  of  the  glazing-glass  being  regulated  by  a  foot 
lever  and  a  rocking  arrangement  fitted  with  springs  at 
the  head  of  the  machine  (see  Fig.  79). 

Iron  machines,  such  as  the  type  shown  at  Fig.  78,  give 
great  satisfaction  for  the  heavier  leathers,  such  as  box- 
calf, &c. ;  in  fact,  some  tanners  use  them  for  the  first 
glazing  of  kid,  but  taken  all  round  the  wooden  "  Bower," 
by  reason  of  its  resiliency  and  cheapness,  is  the  best 
appliance  for  the  glace*  leather  maker  to  put  into  his 
factory.  The  work,  however,  is  rather  trying,  as  the  soft 
leather  has  to  be  "humoured"  to  the  work  with  the 
hands,  whilst  in  the  case  of  the  old-fashioned  stiffer 
leathers,  like  levant,  the  leather  stood  out  boldly  under 
the  pounding  action  of  the  polishing  tools.  Good  super- 
vision pays  in  glazing,  and  new  beginners  should  only 
be  entrusted  to  do  common  goods  for  the  first  glazing. 


$44  LEATHER  MANUFACTURE. 

After  the  skins  have  been  glazed  once  they  are  then 
again  lightly  seasoned,  hung  up  to  dry,  and  glazed  the 
second,  and,  if  necessary,  the  third  time.  This  practically 
completes  the  process,  although  it  is  an  advantage  in 
some  cases  to  wipe  over  the  grain  with  a  clean  oily  rag. 
This  helps  the  finish  to  stand  moisture  and  handling 
better,  and  slightly  softens  the  leather,  but  is  optional, 
and  is  not  followed  out  in  many  factories. 

This,  then,  is  the  end  of  black  glace  or  glazed  goat 
manufacture.  Enough  has  been  said  to  give  readers  a 
good  idea  of  the  process,  and  given  good  skins,  material, 
machinery,  and  skilled  supervision,  a  saleable  article  may 
be  made  by  following  out  the  directions  set  forth. 
Mention  should  be  made,  however,  of  the  fact  that  even 
after  the  leather  is  made,  the  chances  of  commercial 
success  are  much  improved  by  careful  measuring  and 
grading  the  skins  into  the  proper  classes.  Goat  skins 
vary  greatly  in  size,  substance,  texture,  and  fineness  of 
grain,  and  the  selection  and  grading  is  a  work  only  to  be 
found  out  by  experience  in  the  markets  catered  for,  and 
should  be  done  by  trained  sorters,  or  by  the  principal 
himself,  who  fully  realizes  the  responsibility  of  this  final 
operation. 


DYEING  FANCY  SHADES  ON  CHROME  GOAT. 

Before  passing  on  to  a  brief  review  of  the  processes  in 
vogue  for  chroming  box-calf,  &c.,  it  would  be  well  to 
give  a  few  hints  on  the  treatment  of  chrome  goat  skins 
which  are  intended  for  colouring.  As  before  mentioned, 
the  skins  are  sorted  in  the  "  blue "  condition,  i.e.  after 
they  have  been  struck  out  from  the  final  washing  after 
chroming.  The  dyeing  is  usually  carried  out  in  the 
drum  or  paddle,  solutions  of  aniline  dyes  being  used  for 
the  purpose.  Methods  differ  a  good  deal,  but  the  writer 
has  found  the  following  to  give  good  results.  First, 
mordant  the  skins  in  a  weak  solution  of  some  tannin.  A 
mixture  of  cube  gambier  and  fustic  extract  of  about  5 


CHROME  LEATHER  MANUFACTURE.  345 

per  cent,  of  the  wet  weight  of  the  skins,  with  enough 
water  at  about  140°  Fahr.,  will  produce  a  good  foundation 
for  most  of  the  ordinary  shoe  colours.  Sumac  extract  is 
also  useful  for  the  same  purpose.  These  materials  should 
be  carefully  dissolved  and  the  skins  drummed  in  the 
solution  for  about  twenty  minutes.  The  skins  are  then 
either  drained  or  lightly  struck  out  and  fat-liquored.  In 
some  cases  the  fat-liquoring  is  done  after  the  dyeing,  but 
if  the  liquor  is  at  all  alkaline,  the  colour  is  stripped  more 
or  less,  and  often  a  nondescript  sort  of  shade  is  the  result. 

The  hot  fat-liquor  is,  as  in  the  case  of  black  skins, 
added  to  the  drum  whilst  the  goods  are  in  motion,  the 
quantity  being  less,  however,  and  regulated  to  suit  the 
requirements  of  the  particular  sort  of  skin  under  treat- 
ment. After  the  fat-liquor  has  done  its  work  the  surplus 
water  is  run  off  and  the  dye  liquor  added.  The  writer, 
in  actual  practice,  found  it  an  advantage  to  take  the 
skins  from  the  drum,  and  to  fold  them  straight  down 
the  ridges  with  the  grain  outwards.  About  one-third  of 
the  hot  dye  liquor  is  put  in  the  drum,  the  skins  quickly 
entered  and  the  drum  started,  and  the  remainder  of  the 
dye  added  in  successive  portions.  The  time  occupied  by 
the  dyeing  is  about  a  half  to  three  quarters  of  an  hour. 
Although  both  the  basic  and  acid  colours  may  be  used 
for  dyeing  chrome  leather,  the  acid  range  is  preferred 
by  many,  especially  where  the  water  is  hard.  There  is  a 
wide  range  of  these  latter,  and  excellent  shades  can  be 
obtained  by  a  mixture  of  acid  yellows,  brown,  &c.,  shaded 
with  a  little  blue  or  green.  The  amount  of  dye  required 
of  course  varies,  but  from  3  to  6  ozs.  per  dozen  goat  skins 
is  usually  sufficient.  An  American  authority  says  that 
chrome  tanned  skins  may  be  very  satisfactorily  coloured 
with  sulfamine  dyes,  which  require  no  mordant,  and  pro- 
duce full,  clear,  and  uniform  shades  of  colour. 

In  dissolving  the  aniline  dyes  care  should  be  taken  to 
see  they  are  well  strained  through  a  fine  muslin  cloth 
before  the  solution  is  added  to  the  skins  in  the  drum, 
otherwise  the  undissolved  particles  are  apt  to  get  on  the 
grain  of  the  leather  and  cause  unsightly  blotches. 


346  LEATHER  MANUFACTURE. 

Much  space  might  be  taken  up  with  a  variety  of  so- 
called  formulae  for  dyeing,  but  in  the  writer's  opinion  this 
would  be  of  little  practical  value,  owing  to  the  differences 
in  the  requirements  of  the  market,  the  uncertainty  in  the 
nomenclature  of  the  dyes,  and  the  various  methods  of 
working.  Most  of  the  aniline  dye  manufacturers  keep  a 
special  range  of  colours  for  chrome  leather,  and  are,  as  a 
rale,  only  too  glad  to  furnish  what  information  they  can 
on  the  subject.  Mention,  however,  might  be  made  of  a 
new  dyeing  process  by  what  are  known  as  the  Corichrome 
mordants.  These  have  been  put  on  the  market  by  the 
Chemische  Fabrik  Guestrow  of  Mecklenberg,  the  English 
agents  being  Messrs.  W.  and  C.  Pantin,  147,  Upper  Thames 
Street,  London,  E.G.  These  have  been  used  with  success 
on  the  Continent,  and  shades  produced  by  the  Corichrome 
mordants  are  said  to  be  fast  to  light  and  almost  fast  to 
soap  and  alkali.  No  change  is  said  to  take  place  in  the 
shade  in  the  subsequent  fat-liquoring  in  the  drum — not 
even  when  an  alkaline  fat  liquor  is  used.  The  shades 
themselves  are  actually  determined  by  the  Alizarine  or 
fast  mordant  dye-stuffs  used  in  the  dye-bath  (grounding- 
bath),  and  are  perfectly  developed  by  the  subsequent 
treatment  in  the  Corichrome  developing  bath  (fixing-bath). 

•There  seems  to  be  a  great  future  before  this  method  of 
chrome-leather  dyeing,  as  it  promises  to  do  away  with 
many  of  the  difficulties,  so  far  incidental  to  the  process, 
which  are  many  and  formidable. 

After  dyeing  the  skins  are  sometimes  fat- liquored — if 
this  has  not  been  done  before  as  just  described — and, 
whether  fat-liquored  at  this  stage  or  no,  they  are  struck 
out,  glycerined,  reset,  oiled  and  dried  just  as  described 
for  black  glace. 

The  finishing  is  much  the  same,  but  it  is  often  necessary 
to  "  top-up  "  the  grain  with  some  fairly  strong  solution  of 
colour,  after  the  first  staking,  to  produce  the  exact  shade 
required.  The  "  season  "  used,  too,  must  obviously  be 
different,  and  the  writer  has  found  nothing  better  for  the 
purpose  than  a  weak  albumen  solution,  tinted  with  a  suit- 
able dye.  Dry  albumen  for  the  purpose  should  be  left  to 


CHROME  LEATHER  MANUFACTURE.  347 

dissolve  in  cold  water,  and  kept  sweet  with  a  little  dis- 
solved phenol.  This  should  be  made  in  a  moderately 
strong  solution,  and  diluted  to  the  consistency  required 
with  cold  water,  and  applied  with  a  soft  sponge  or  rag, 
carefully  and  evenly. 

The  final  staking  and  glazing  is  followed  out  in  the 
same  manner  as  described  for  black  work,  more  care,  if 
anything,  being  used  to  keep  the  skins  clean  and  of  even 
shade.  Experiments,  of  course,  should  be  on  a  small 
scale,  and  frequent  tests  made  before  deciding  to  put  a 
large  pack  of  valuable  skins  out  for  any  particular  shade. 


CHAPTER  XXVIII. 
BOX-CALF  MANUFACTURE. 

Striking-out  and  Shaving. — Fat-Liquoring. — Dyeing  Black. — Finishing 
Operations. 

THE  preparatory  stages  of  chrome  calf  manufacture  are 
much  the  same  as  for  wax  or  kid  calf,  special  care  being 
taken  to  rid  the  pe.lt  of  lime,  &c.  For  this  reason  the 
excrement  pure  or  bate  is  often  supplemented  by  wash- 
ing the  skins  in  lactic  acid  solution,  or  the  bran  drench, 
the  final  scudding  being  also  very  carefully  carried  out. 
Some  tanners  also  give  the  skins  a  pickle  of  acid  and 
salt  before  chroming,  claiming  for  this,  that  it  makes  a 
softer  and  fuller  leather.  About  50  Ibs.  of  salt  and 
about  5  pints  of  sulphuric  acid  dissolved  in  sufficient 
water  is  enough  for  one  hundred  skins,  the  skins  being 
pickled  in  about  four  to  six  hours,  and  the  surplus  liquor 
drained  off  before  the  goods  are  entered  into  the  chrome 
bath. 

Salt  is  also  often  given  the  skins  in  the  drum  before 
chroming,  or  in  the  chrome  bath,  as  it  tends  to  keep  the 
grain  from  becoming  wrinkled  and  drawn  in  the  process, 
and  produces  a  softer  leather.  It  also  keeps  the  fibre  of 
the  pelt  open,  and  helps  the  penetration  of  the  chroming 
liquor. 

Calf  skins  may  either  be  chromed  by  the  two-bath 
method,  as  described  for  goat  skins,  or  by  what  is  known 
as  the  one-bath  method.  This  latter  greatly  simplifies 
the  process  as  it  avoids  the  uncertainties  of  the  chemical 


BOX-CALF  MANUFACTURE.  349 

action  incidental  to  the  two-bath  method.  Various  chrome 
liquors  are  now  on  the  market,  but  the  first  one  of  any 
great  value  was  introduced  by  Martin  Dennis,  of  America, 
and  is  still  sold  under  the  name  of  "Tanolin."  Accord- 
ing to  his  original  patent  his  liquor  is  obtained  as 
follows : — First,  a  solution  of  neutral  chrome  chloride  is 
obtained  by  solving  a  certain  amount  of  chromic  oxide 
in  hydrochloric  acid,  care  being  taken  that  there  is  always 
a  surplus  of  chromic  oxide,  i.e.  there  should  always  be 
more  chromic  oxide  present  than  the  added  amount  of 
hydrochloric  acid  is  able  to  solve.  To  this  solution 
caustic  soda,  or,  better  still,  bicarbonate  of  soda,  is  care- 
fully added  until  a  permanent  precipitate  of  chrome 
hydroxide  is  formed. 

In  this  manner  chrome-oxychloride  or  basic  hydro- 
chloric chrome  oxide  is  obtained,  a  compound  easily 
soluble  in  water,  which  very  easily  parts  with  the  super- 
fluous chromic  oxide,  especially  in  the  presence  of  bodies 
possessing  great  affinity  to  chromic  oxide ;  for  example, 
gelatinous  hide  substance.  Besides  chromic  oxide  the 
solution  also  contains  common  salt  (sodium  chloride), 
which  is  formed  by  adding  the  bicarbonate  of  soda  to 
the  hydrochloric  chrome  oxide.  The  presence  of  salt  is 
of  great  use  in  the  tanning  process,  as  it  prevents  the 
swelling  of  the  hides  in  the  liquor,  and  helps  to  promote 
the  tanning  process.  Very  often  more  salt  is  added  to 
the  bath  to  ensure  a  good  tannage.  By  these  means  a 
stock  of  tanning  liquor  is  obtained  which  is  suitably 
diluted  before  the  skins  are  placed  into  same.  The  pro- 
cess is  mostly  carried  on  in  paddles,  beginning  with  a 
fairly  diluted  solution,  and  adding  more  of  the  stotk 
tanning  liquor  from  time  to  time,  until  the  skins  are 
struck  through  a  green  colour  in  the  thickest  part.  This 
process  generally  lasts  from  ten  to  forty-eight  hours, 
according  to  the  substance  of  the  skins.  The  surplus 
of  acid  in  the  skins  is  neutralised  by  giving  them  a 
bath  containing  either  calcium  carbonate,  lead  carbonate, 
barium  carbonate,  or  similar  substances. 

A  good  formula  published  some  time  ago  by  Professor 


350  LEATHER  MANUFACTURE. 

H.  E.  Procter  is  as  follow : — Take  10  per  cent,  (of  the 
weight  of  the  skins)  of  chrome  alum,  arid  solve  same  in 
a  sufficient  quantity  of  water,  and  solve  separately  2J  to 
3J  per  cent,  of  soda.  Add  sufficient  of  the  soda  solution 
to  the  chrome-alum  solution  until  a  permanent  precipitate 
of  chrome  oxyhydrate  begins  to  form,  and  then  add  a 
small  quantity  of  common  salt. 

A  writer  in  the  Leather  Trades  Eeview  states  that  he 
has  also  obtained  excellent  results  from  a  chrome  liquor 
prepared  in  the  following  manner : — Ten  parts  of  chrome 
alum  are  solved  in  sufficient  hot  water,  arid  the  solution 
allowed  to  cool  down,  then  a  separate  solution  of  three 
parts  soda  is  made.  Add  sufficient  soda  solution  to  the 
chrome-alum  solution  until  a  permanent  precipitate  of 
chrome  hydroxide  appears,  and  then  add  lactic  acid 
until  the  precipitate  is  just  solved,  and  a  clear  liquor 
is  obtained. 

With  this  solution  make  a  fairly  weak  bath  to  start 
with,  and,  after  allowing  the  skins  to  paddle  for  a  couple 
of  hours,  add  more  of  the  chrome  solution,  continuing 
to  do  so  at  short  intervals  until  the  skins  are  struck 
through  a  greenish  colour.  The  old  bath  may  be  used 
for  a  new  lot  of  skins,  and  a  new  bath  made  into  which 
the  second  lot  of  skins  are  placed  when  the  first  bath  is 
used  up,  and  so  on. 

Amongst  the  various  ready-made  chrome  liquors  on  the 
market  the  writer  has  heard  that  prepared  by  Prenzlau's 
Fabrikwerke,  Hamburg,  spoken  well  of.  This  is  sold 
under  the  name  of  "Corin,"  and  the  following  short 
description  of  the  method  of  its  application  may  be  taken 
as  being  fairly  representative.  The  skins  are  first  placed 
into  a  4  per  cent,  solution  of  "  Corin,"  and  are  allowed  to 
paddle,  then  more  "  Corin "  is  added  at  short  intervals 
until  all  in  all  about  a  10  per  cent,  solution  is  obtained, 
in  which  the  skins  remain  until  tanned.  The  Vacuum 
Oil  Co.,  Ltd.,  York  House,  Norfolk  Street,  Strand, 
London,  W.C.,  also  sell  a  one-bath  chrome  liquor  which 
has  given  great  satisfaction  to  makers  of  box  and  willow 
calf. 


BOX-CALF  MANUFACTURE.  351 

Generally  speaking,  all  one-bath  chrome  liquors  are 
sold  in  a  highly  concentrated  form,  and  the  makers  give 
pretty  accurate  directions  as  to  their  employment,  and 
in  some  cases  even  send  out  competent  instructors  to 
introduce  them. 

Both  the  paddle  and  drum  are  used  in  box-calf  tan- 
ning, the  latter  perhaps  being,  on  the  whole,  the  most 
convenient.  After  tanning,  the  skins  are  well  washed 
in  a  borax  solution  of  about  2  Ibs.  per  cent,  of  pelt 
weight,  and  finally  in  clean  water  until  they  are  free 
from  salt  and  acid. 

Striking-out  and  Shaving. — The  skins  are  then  well 
struck  out,  as  described  in  the  former  chapter  on  glace- 
goat  manufacture,  and  are  now  shaved.  This  is  now 
almost  always  done  by  machine,  and  a  good  operator  can 
do  from  fifteen  to  twenty  dozen  skins  per  day,  if  the 
leather  is  in  good  order,  and  does  not  require  much 
reducing.  Care  should  be  taken  to  see  the  cutting 
cylinder  has  suitable  knives  and  is  in  good  condition ; 
the  grinding  of  the  emery  wheel  should,  as  far  as  possible, 
be  carried  out  when  the  skin  is  not  actually  under  treat- 
ment, otherwise  the  particles  of  steel  may  cause  trouble 
at  a  later  stage,  especially  if  fancy  colours  are  to  be 
produced.  It  is  convenient  after  shaving  to  weigh  the 
skins,  as  it  furnishes  a  base  for  the  calculation  of  the  fat- 
liquor,  &c.,  later  on.  Care  should  also  be  taken  that  the 
leather  is  not  allowed  to  get  dry,  for  it  is  impossible  to 
damp  chrome  leather  back,  as  is  the  case  with  vegetable 
tanned  leather. 

The  skins  are  often  at  this  stage  blue-backed  in  the 
drum,  logwood,  methyl  violet,  nigrosine,  &c.,  being  used. 

Fat-Liquoring. — This  is  done  in  much  the  same  manner 
as  already  described  for  goat  leather,  the  oily  emulsion 
being  added  in  a  heated  condition  to  the  goods  in  the 
drum.  Olive,  castor,  and  neatsfoot  oils  are  used  in  con- 
junction with  various  soaps,  &c.  Turkey  red  oil  is  also 
used,  but  probably  the  best  all-round  results  are  obtained 
from  neatsfoot  oil  and  egg  yolk.  The  quantity  of  liquor 
given  the  skins  varies  a  good  deal,  but  averages  from 


352  LEATHER  MANUFACTURE. 

about  5  to  10  per  cent,  of  the  shaved  weight.  This, 
however,  is  a  point  best  found  out  by  experience. 

A  good  quality  fat-liquor  soap  recommended  by 
Professor  Procter  is  made  as  follow: — 2  Ibs.  of  caustic 
soda  are  solved  in  about  8  pints  of  water.  This  solution 
is  poured  into  20  pints  of  castor  oil,  previously  heated  to 
86°  Fahr.,  continually  stirring  the  whole  time  until  the 
soap  becomes  thick ;  after  this,  the  tub  containing  the 
soap  is  covered  and  allowed  to  remain  overnight  in  a 
warm  place.  The  soap  is  now  ready  for  use.  It  is  as 
well,  but  not  essential,  to  melt  the  soap  again  before  use 
in  a  jacketed  pan  containing  a  stirring  apparatus.  By 
means  of  this  apparatus  a  better  and  more  even  mixing 
of  the  soap  is  obtained. 

The  following  recipes  for  fat-liquors  have  also  been 
collected  and  published  by  a  writer  on  the  subject : — 

1.  One  pint  neatsfoot  oil  and  1  pint  cod  oil  are  stirred 
together  with  1  pint  of  a  10  per  cent,  solution  of  soda, 
and  this  mixture  is  poured  into  a  hot  solution  of  3  Ibs.  of 
soap  chips  in  6  pints  of  boiling  water,  continually  stirring 
the  whole  time.     Five  to  10  per  cent,  of  shaver's  weight 
are  then  added  to  the  necessary  amount  of  water,  i.e.  for 
100  Ibs.  of  leather  (shaver's  weight)  about  10  gallons  of 
hot  water  are  taken. 

2.  4  Ibs.  of  soft  soap  are  solved  in  1  gallon  of  boiling 
water,  then  add  1J  Ibs.  of  degras  and  £  Ib.  of  soda  pre- 
viously solved  in  water.     Five  to  10  per  cent,  of  this 
mixture  is  thinned  with  the  necessary  amount  of  water 
as  above. 

3.  5  Ibs.  of  soap  chips  are  solved  in  sufficient  boiling 
water,  then  warm  4  pints  of  neatsfoot  oil,  and  stir  same 
into  the  soap  solution.     Dilute  the  emulsion  as  above. 

4.  Dilute  6  Ibs.  of  soft  soap  in  boiling  water,  then  add 
5  pints  of  linseed  oil  to  same,  continually  stirring  until 
a  good  emulsion  is  obtained.     Dilute  same  as  above. 

5.  10  Ibs.  of  soap  chips  are  solved  in  boiling  water,  then 
add  4  gallons  of  neatsfoot  oil,  and  10  Ibs.  of  egg  yolk 
when  it  has  cooled  down  sufficiently;  stir  until  thoroughly 
emulsified,  and  dilute  as  above. 


BOX-CALF  MANUFACTURE.  353 

6.  Fifteen  parts  of  olive-oil  soap  are  emulsified  with 
4  J  parts  of  olive  oil,  and  diluted  as  above. 

7.  For  fancy  shades  of  colour  the  following  fat -liquor 
has  been  recommended :   £  per  cent,  castor-oil  soap   or 
olive-oil  soap  and  f  per  cent,  castor  oil  are  stirred  together 
until  properly  emulsified  and  diluted  as  above. 

8.  The  following  fat-liquor  is  recommended  by  Jettmar : 
3  Ibs.  of  castor-oil  soap,  2£  Ibs.  of  glycerine,  \\  Ibs.  of 
castor  oil  emulsified  with  10  pints  of  boiling  water. 

Whatever  fat-liquor  is  employed,  it  should  be  added 
warm  to  the  goods  in  the  drum  whilst  in  motion,  a  fresh 
liquor  being  either  made  by  boiling  it  under  a  steam-pipe 
or  by  mixing  in  an  emulsifier. 

The  liquor  is  best  added  by  a  suitable  arrangement  at 
the  side  of  the  drum,  which  allows  it  to  go  through  the 
hollow  axle.  If  the  drum  is  warmed  up,  so  much  the 
better,  and  it  will  be  found  that  practically  the  whole  of 
the  fatty  matter  of  the  liquor  will  have  been  absorbed  in 
about  twenty  minutes  to  half  an  hour. 

Dyeing  Black. — After  fat-liquoring,  the  skins  are  dyed 
black,  much  the  same  process  being  used  as  that  described 
for  glace  goat.  The  skins  are  folded  grain  out  from  head 
to  tail,  passed  first  through  a  strong  warm  logwood  de- 
coction, and  then  quickly  through  a  black  or  iron  striker. 
A  good  striker  consists  of  5  Ibs.  of  copperas  and  1 J  Ibs.  of 
blue  vitriol  dissolved  in  20  gallons  of  boiling  water. 
This  is  made  up  to  40  gallons,  and  about  J  Ib.  of  ground 
nut-galls  added.  The  following  iron  blacks  have  also 
been  published  by  an  experienced  writer  on  the  subject : — 

1.  Solve  10  Ibs.  of  iron  vitriol  (copperas)  in  8  gallons 
of  water,  and  then  add  sufficient  ammonia  until  a  greenish 
precipitate  begins   to   form;   add   acetic   acid  in  small 
quantities  until  the  precipitate  vanishes,  and  a  clear  yellow 
solution  is  obtained,  which,  when  applied  to  the  skins 
with  a  brush,  will  give  a  fine  deep  black. 

2.  A   cheaper  black   is   obtained  by  filling  a  barrel 
three-parts  full  of  old  hoop  iron,  which  should  be  devoid 
of  rust,  adding  about  4  gallons  of  water  and  about  4  pints 
of  vinegar.     Place  the  barrel  in  a  warm  place,  and  after 

2  A 


354  LEATHER  MANUFACTURE. 

about  ten  days  fermentation  sets  in,  which  may  be  noticed 
by  the  froth  which  collects  on  the  surface.  The  froth 
should  be  removed  from  time  to  time,  and  in  about  three 
weeks'  time  the  black  is  ready  for  use.  Before  applying 
it  to  the  skin,  about  equal  parts  of  stale  beer  should  be 
added  to  the  black  to  thin  it  down. 

3.  Another  good  black  is  obtained  by  solving  4  parts 
of  iron  vitriol  and  1  part  of  copper  vitriol  (sulphate  of 
copper)  in  20  parts  of  water,  and  adding  3  parts  of  stale 
beer. 

The  blacking  process  may  also  be  done  by  brushing 
the  solution  on  the  skins,  which  are  sleeked  out  on  a  table, 
or  the  black  may  be  given  in  a  tumbler.  A  good  deal 
depends  on  the  general  arrangement  of  the  work,  and  no 
definite  rule  can  be  laid  down.  Some  manufacturers 
claim  good  results  by  the  use  of  aniline  blacks,  and  it  is 
certain  there  is  not  the  tendency  to  brittle  grain,  such  as 
occurs  at  times  with  the  iron  striker  on  black  goods. 
Others  state  the  iron  striker  gives  the  best  all-round 
results ;  but  the  operation  should  be  conducted  by  a 
skilled  dyer.  If  aniline  blacks  are  used  for  blacking 
after  fat-liquoring,  a  little  acetic  acid  must  be  added  to 
the  dye  solution  until  it  is  slightly  acid.  This  will 
counteract  the  effect  of  the  alkali  given  by  the  fat-liquor 
soap  to  the  liquor.  In  dyeing  chrome  calf  in  a  tumbler 
a  1  to  1£  per  cent,  solution  of  the  aniline  black  is  given, 
and  2  to  3  per  cent,  of  salt  added.  The  temperature 
should  be  kept  up  to  about  140°  Fahr.,  the  time  occupied 
being  about  half  an  hour. 

After  the  skins  have  been  dyed,  they  are  carefully 
rinsed  in  water,  and  set  or  struck  out  by  hand  or 
machine.  They  are  then  given  a  coat  of  warm  neatsfoot 
oil  on  the  grain  side,  and  sharply  dried  in  a  heated 
chamber.  Many  tanners  prefer  to  strain  the  skins  out 
on  wooden  frames  before  drying,  and  doubtless  this 
gives  a  better  measurement,  and  preserves  the  pattern 
on  the  skin  much  better  than  would  otherwise  be  the 
case. 

Finishing  Operations, — When  the  skins  are  dry  they 


BOX-CALF  MANUFACTURE.  355 

are  taken  to  a  cool  room  and  allowed  to  lay  for  a  few  days 
until  they  are  wanted.  They  are  then  slightly  damped 
by  being  covered  with  moist  sawdust,  and  staked.  The 
method  and  machine  used  for  the  purpose  is  much 
the  same  as  that  described  for  glace  goat.  The  work, 
however,  is  harder,  and  a  good  deal  of  judgment  has  to  be 
used  to  avoid  over-softening  the  flanks  and  bellies  of  the 
skins.  The  skins  are  then  hung  up  and  dried  slightly, 
and  restaked,  after  which  the  edges  are  trimmed  with 
sharp  shears. 

Box-calf  is  then  given  a  seasoning,  i.e.  some  suitable 
solution  is  rubbed  on  the  grain  to  prepare  it  for  the  sub- 
sequent glazing.  Nearly  every  tanner  has  his  own  formula 
for  the  purpose ;  but  the  following  will  be  found  reliable  : 
6  ozs.  of  nigrosine  dissolved  in  5  gallons  of  water ;  add 
2  pints  of  bullock's  blood,  5  ozs.  of  glycerine,  and  8  ozs. 
of  ammonia. 

Another  recipe :  5  ozs.  of  copperas  are  dissolved  in 
5  gallons  of  logwood  liquor  ;  add  to  this  2  pints  of  blood, 
5  ozs.  of  glycerine,  and  8  ozs.  of  ammonia. 

A  good  formula  used  with  success  on  the  Continent  is 
as  follows  :  Beat  up  the  white  of  three  eggs,  and  then  add 
2  pints  of  logwood  solution ;  well  strain,  and  add  1 J  pints 
of  ox  blood  and  J  pint  of  milk.  Weak  solutions  of  albu- 
men and  linseed  decoction  are  also  sometimes  used,  these 
latter,  however,  being  more  suited  to  seasonings  for  fancy 
colours,  where  the  above  materials  are  not  suitable. 

In  seasoning,  only  sufficient  of  the  mixture  should  be 
applied  to  the  grain  with  a  suitable  pad  to  enable  the 
glazing  to  be  executed  properly,  otherwise  the  latter 
process  will  not  be  a  success,  whilst  the  excess  of  season- 
ing is  likely  to  peel  off  in  the  subsequent  boarding. 
When  the  season  has  properly  penetrated,  the  skins  are 
then  glazed  by  machine.  There  are  several  types  in  use, 
and  each  make  possesses  useful  features.  The  pressure 
used  in  glazing  must  not  be  too  great,  otherwise  the 
glazing  glass  is  apt  to  leave  marks  on  the  skin  which  are 
difficult  to  remove. 

After  the  first  glazing  is  complete,  the  skins  are  grained 


356  LEATHER  MANUFACTURE. 

by  means  of  the  ordinary  cork-covered  pommel  or  arm- 
board.  In  box-calf  it  is  usual  to  grain  two  ways  only, 
once  from  the  head  to  the  tail,  and  then  from  belly  to 
belly.  It  should  be  noted,  too,  that  it  is  often  advisable 
in  the  case  of  coarse  flanky  skins  to  lightly  emboss  with 
a  suitably  engraved  roller  before  graining ;  this  prevents 
a  coarse,  unsightly  "  break,"  but  only  sufficient  pressure 
should  be  used  to  assist  the  formation  of  the  natural 
grain,  as  an  artificial-looking  break  is  strongly  objected  to. 

After  graining,  the  skins  are  again  seasoned  lightly ; 
care  should  be  taken  the  season  is  not  applied  too  strong, 
and  a  shank  should  be  tested  once  or  twice  before  season- 
ing the  whole  lot,  and  the  season  modified  or  weakened  to 
suit  requirements.  After  the  second  seasoning  a  second 
glazing  is  given,  first  with  a  fairly  heavy  pressure,  and 
finally  with  just  sufficient  pressure  to  remove  the  tool 
marks,  streaks,  &c.  A  final  light  boarding  or  graining 
completes  the  process,  and  after  the  skins  have  been 
sorted  into  qualities  and  sizes,  the  goods  are  ready  for 
the  market. 

In  conclusion,  it  may  be  added  that  methods  in  vogue 
vary  a  great  deal,  but  if  the  above  directions  are  followed 
out,  and  practical  common  sense  applied  where  modifica- 
tions are  necessary,  there  is  no  reason  why  a  good  saleable 
article  should  not  be  turned  out.  The  chrome  process, 
however,  requires  constant  attention  to  get  uniform 
results,  and  experiments  on  a  small  scale  are  advisable 
until  success  can  reasonably  be  anticipated. 


CHAPTER  XXIX. 
CHAMOIS,    OR   OIL-LEATHER  MANUFACTURE. 

Preparation  and  Frizing. — Drenching. — Stocking  or  Milling  in  Oil.— 
Pressing  and  Washing. — Finishing. — Chamois  Glove  Leather. — 
Bleaching. — Tucking.— Colouring. — Buff  Leather. — Liming.— Pre- 
paring and  Milling.— Scudding  and  Wash-house. — Buck  Skin  Dress- 
ing.— Milling  or  Stocking.— Scudding  and  Wash-house. 

THE  manufacture  of  "chamois,"  or  oil-leather,  is  still 
one  of  the  most  important  branches  of  the  leather  in- 
dustry, and  an  enormous  home  and  export  trade  is  done 
in  this  material.  The  preservative  or  tanning  principle 
is  not  well  understood,  but  it  probably  depends  upon  an 
oxidation  of  the  fats  with  which  the  raw  pelt  is  treated. 
It  should  be  mentioned  that  oil  tanning  is  one  of  the 
oldest  methods  known  in  the  preservation  of  animal 
skins,  and  is  still  practised  to  this  day  by  savage  races. 

Chamois  leather  is  now  usually  manufactured  from  the 
flesh  splits  or  "linings"  of  the  sheep  skin,  whilst  white, 
or  "  buff "  leather,  formerly  used  so  extensively  for 
military  accoutrements,  is  made  from  heavier  hides  by 
the  same  process  with  slight  modifications.  The  manu- 
facture of  chamois  is  mainly  in  a  few  large  hands,  as  the 
plant  is  rather  expensive,  and  the  amount  of  capital  re- 
quired considerable.  Most  tanners  utilize  the  entire  sheep 
skin,  the  grain  side  being  tanned  with  sumac  and  sold 
under  the  name  of  "skiver"  for  a  variety  of  cheap  pur- 
poses, whilst  the  flesh  split  is  either  turned  into  chamois 
or  "  pickled  "  with  sulphuric  acid  and  salt  for  export  as 
the  position  of  the  market  demands. 


358  LEATHER  MANUFACTURE. 

Sheep  skins  are  first  de-wooled  by  the  fellmonger,  and 
eventually  collected  by  the  dresser,  who  sorts  them 
for  the  most  suitable  purposes.  Those  intended  for 
splitting  are  given  a  further  liming  to  plump  them;  and 
are  then  split  on  a  machine  with  a  rapidly  vibrating 
knife.  Assuming  the  flesh  splits  are  to  be  dressed  as  wash 
or  chamois  leather,  the  process  is  as  follows  : — 

Preparation  and  Prizing. — After  splitting,  the  linings 
are  again  put  into  lime,  the  lime-pits  being  so  arranged 
that  the  solutions  are  of  a  gradually  progressive  strength. 
The  goods  are  drawn  frequently  and  the  lime  strengthened 
as  required.  This  stage  of  liming  usually  lasts  from  ten 
to  fourteen  days,  according  to  the  class  of  skins  and  their 
condition.  The  linings  are  at  the  end  of  this  time  firm  and 
in  good  condition  for  frizing,  and  all  rough  flesh  and 
roughness  can  be  easily  removed  with  a  sharp  knife  on 
the  beam.  Unskilled  labour  is  often  utilized  for  this 
purpose,  and  the  operation  is  also  done  by  machinery ; 
but  it  is  doubtful  if  much  real  saving  is  effected.  Skins 
badly  frized  are  said  to  require  more  oil  and  to  want  extra 
work  in  the  grounding  operation. 

Drenching. — This  process  is  usually  carried  out  in  tubs 
or  vats,  although  in  some  of  the  larger  works  the  drum  or 
paddle  is  used.  According  to  a  writer  in  the  Leather 
Trades  Beview,  the  tubs  used  are  from  half  to  two-thirds 
filled  with  water  at  a  temperature  of  about  70°  to  80° 
Fahr.  To  this  water  is  added  one  to  one  and  a  half 
buckets  of  scalded  bran  or  meal,  the  bucket  reckoned  as 
holding  about  three  gallons.  Previous  to  drenching,  the 
skins  are  well  washed,  either  in  a  drum  or  paddle,  through 
which  an  abundant  supply  of  clean  water  is  kept  running. 
This  will  free  them  from  surplus  lime  and  other  objection- 
able matter,  and  show  a  saviug  in  the  amount  of  bran 
required.  The  skins  are  then  placed  in  the  drench  tubs 
and  are  continuously  stirred,  though  it  is  much  quicker 
to  use  the  paddle  for  the  purpose.  This  will  accomplish 
the  delinking  or  drenching  process  in  about  six  hours, 
against  twelve  to  twenty-four  required  in  the  tubs.  No 
definite  rale  can  be  laid  down  as  to  the  amount  of 


CHAMOIS,    OR   OIL-LEATHER  MANUFACTURE.        359 


drenching  required,  but  an  experienced  workman  will  be 
able  to  tell  when  the  process  has  been  carried  far  enough 
by  the  feel  and  general  appearance  of  the  skins. 

AVhen  the  skins  have  been  drenched,  they  are  well 
pressed  to  remove  surplus  moisture  and  grease.  This  is 
usually  done  in  an  hydraulic  press,  the  skins  being 
arranged  between  plates,  sacking,  and  wood  blocks,  the 
whole  process  taking  about  an  hour. 

Stocking  or  Milling  in  Oil. — When  the  skins  are  ready 
for  milling  or  stocking — the  process  being  done  in  the 
machine  shown  at  Fig.  G  (page  111) — each  skin  is  well 
shaken  out  to  get  rid  of  adhering  bran  or  meal,  and  they 
are  allowed  to  cool  by  being  thrown  on  the  floor,  care  being 
taken  to  avoid  getting  them  dirty.  They  are  then  stocked 
for  about  an  hour  to  get  them  in  uniform  condition. 
Then  they  are  taken  from  the  stocks  and  a  three-gallon 
pail  of  cod  oil  is  got  ready,  also  a  sprinkler  made  of 
heather  sprigs.  With  this,  one  operative  sprinkles 
the  skins,  whilst  another  gradually  throws  the  skins 
into  the  stocks  until  sufficient  oil  has  been  given.  They 
are  then  milled  for  three  or  four  hours,  when  it  will 
be  found  the  skins  are  covered  with  soap,  and  will  also 
have  a  soapy,  slippery  feeling  when  handled.  The 
skins  are  now  drawn  from  the  stocks  and  taken  to  the 
sheds  for  air-drying,  no  artificial  heat  being  applied  at 
this  stage. 

After  about  a  day's  steady  drying  the  skins  are  again 
stocked  and  sprinkled  with  oil  as  before,  the  time  being 
usually  three  hours.  They  are  now  drawn  and  stoved  at 
a  temperature  of  about  100D  Fahr.,  the  operation  resulting 
in  making  the  skins  a  brownish  colour.  This  process 
of  stocking  and  drying  is  repeated  several  times,  until 
the  final  heating  off,  when  the  skins  are  hooked  by  the 
neck  on  ranges  very  closely  in  the  drying  stove.  In  this 
stove  the  heat  is  raised  to  about  150°  to  160°  Fahr.,  when 
a  sharp,  astringent  odour  will  be  given  off. 

The  skins  are  then  thrown,  whilst  in  the  heated  con- 
dition, in  bins  or  casks,  well  trodden,  and  covered  with 
sacking  to  retain  the  heat.  The  temperature  will  at  once 


360  LEATHER  MANUFACTURE. 

begin  to  rise,  and  the  skins  will  require  most  careful 
attention.  The  millman  should  go  frequently  from  bin 
to  bin  and  note  the  temperature.  At  intervals  they  are 
turned  by  casting  them  into  another  bin,  the  workman 
using  gloves  for  the  purpose,  and  the  goods  well  trodden 
down  by  a  lad.  This  is  repeated  until  the  skins  are 
heated  off,  a  point  only  indicated  by  experience. 

Care  should  be  taken  that  there  is  no  surplus  oil  or 
moisture  on  the  goods,  or  damage  is  very  likely  to  result. 
The  workmen  should  also  wear  goggles  to  protect  the 
eyes,  as  the  vapour  arising  from  the  skins  is  irritating. 
Sufficient  goods  should  be  always  available  to  keep  up 
the  process  of  heating,  otherwise  parts  of  the  leather  will 
remain  green,  and  will  become  drawn  when  treated 
with  the  alkalies  later  on.  When  the  goods  have 
assumed  a  characteristic  dark-brown  colour  they  are 
spread  around  to  cool,  and  are  ready  for  pressing  and 
washing. 

Pressing  and  Washing. — The  skins  are  then  thrown 
into  a  vat  of  water  at  a  temperature  of  about  110°  Fahr., 
and  well  pressed  in  the  hydraulic  press.  Grease  will  soon 
begin  to  exude,  and,  later  on,  the  substance  known  as 
sod  oil,  all  of  which  being  valuable,  is  carefully  collected 
and  treated  further  if  necessary. 

When  the  skins  are  sufficiently  pressed,  they  are  then 
well  washed  in  an  alkaline  solution  prepared  as  follows : 
For  ten  dozen  skins,  dissolve  4  Ibs.  of  soda  ash  and  2  Ibs. 
of  soda  crystals  in  sufficient  water  at  a  temperature  of 
120°  Fahr.  The  washing  is  often  done  in  a  paddle,  about 
twenty  dozen  skins  being  paddled  for  about  two  hours. 
The  goods  are  now  wrung  out  and  the  liquor  run 
away.  Fresh  water  is  then  run  in  the  paddle  and  the 
heat  raised  to  130°  or  140°  Fahr.,  and  the  skins  given 
another  hour's  washing.  In  most  places  some  arrange- 
ment is  made  to  save  the  liquor — the  first  being  especially 
valuable — as  this  contains  emulsified  fats  which  are 
worth  recovering. 

Wash-leathers  may  either  be  dried  alter  the  second 
washing  or  given  a  further  liquor  to  improve  their 


CHAMOIS,   OR  OIL-LEATHER  MANUFACTURE.       361 

pliability.  A  practical  writer  on  the  subject  gives  the 
following  method  of  preparation :  Having  run  off  the 
second  liquor,  make  a  third  in  paddle  as  follows :  in  a 
small  mixer  or  tub  put  10  Ibs.  of  cod  oil  (about  1  gallon), 
add  20  Ibs.  of  soft  soap ;  stir  the  two  well  together  till 
the  mixture  becomes  stiff,  then  add  one  gallon  of  boiling 
water  until  all  soap,  oil,  and  water  are  thoroughly  blended. 
Take  of  this  liquor  3  to3j  gallons  to  the  paddle  of  goods, 
and  run  for  one  hour ;  then  draw  goods,  take  to  either 
wringing  machine  or  hydro-extractor. 

The  skins  are  now  taken  to  the  drying  sheds  to  be 
dried  with  air  or  artificial  heat,  being  hooked  by  the 
two  hind  shanks  on  tenter-hooks  from  rail  to  rail ;  when 
dry  they  are  taken  to  warehouse,  and  are  now  called 
"  crust "  leather. 

For  "fleshers,"  or  heavier  linings,  the  process  is 
prolonged,  and  in  washing  the  amount  of  materials 
is  increased. 

Finishing.— In  this  condition  the  goods,  as  crust 
chamois,  are  often  sold  to  dressers  and  others,  who  make 
a  speciality  of  finishing  for  the  market.  The  skins,  after 
sorting  into  sizes  and  qualities,  are  first  staked,  either  by 
the  arm  or  upright  stake,  and  are  then  levelled  and 
worked  out  by  the  moon-knife  on  the  perch;  this  last 
operation  being  a  skilled  operation,  and  one  requiring 
great  care.  The  skin  is  extended  in  every  possible  way 
by  the  workman  until  it  is  thoroughly  soft,  and  the  fibre 
can  be  pulled  in  any  direction. 

The  goods  when  finished  are  then  carefully  trimmed 
with  shears  around  the  edges,  and  the  holes,  where 
possible,  sewn  up  by  hand  or  machine.  They  are  then 
carefully  sorted  into  qualities  and  sizes — the  sorter 
stretching  each  skin  as  much  as  possible — and  eventually 
put  up  into  bundles  of  thirty,  known  technically  as  a 
"  kip."  These  kips  vary  in  price,  some  of  them  coming 
down  as  low  as  five  shillings,  whilst  others  may  be  quoted 
at  fifty  shillings. 

Chamois  leather  is  almost  universal  in  its  application, 
being  used  by  the  tailor,  the  shoemaker  for  boot  linings, 


362  LEATHER  MANUFACTURE. 

the  fancy  leather  goods  maker,  and  for  an  endless  variety 
of  domestic  purposes.  A  large  export  trade  is  also  done 
in  this  material,  America  being  one  of  the  best  customers 
of  England,  whilst  Australia,  Germany,  France,  Italy, 
and  South  America  also  take  large  quantities  from  our 
market. 

Chamois  Glove  Leather.  —The  stoutest  and  best  skins 
are  often  sorted  out  in  the  crust  condition,  and  finished 
specially  for  glove  leather.  They  are  first  well  grounded 
with  a  moon-knife  on  the  side  which  is  the  most  suitable 
for  colouring.  After  this  "  paring  "  operation,  they  are 
then  carefully  run  on  an  emery  wheel  to  produce  a  fine 
smooth  surface,  when  they  are  ready  for  bleaching. 

Bleaching — In  order  to  produce  good  clear  colours  on 
chamois  it  is  necessary  to  bleach  the  leather.  This  is 
still  done  by  exposure  to  light,  the  process  taking  two  or 
three  days  in  summer  and  as  many  weeks  in  winter.  The 
skins  are  first  well  saturated  with  a  warm  solution  of 
soapy  water,  made  by  dissolving  a  sufficient  quantity  of 
soft  soap  in  it,  and  are  then  taken  to  a  suitable  grass 
plot,  the  side  to  be  bleached  and  coloured  being  exposed 
to  the  light.  This  operation  is  repeated  daily  until  the 
desired  result  is  obtained,  when  the  goods  proceed  to  the 
next  operation,  known  as  tucking. 

Tucking — The  skins  are  then  thoroughly  wetted 
through  in  warm  water,  and  are  then  either  wrung  or 
run  in  a  hydro-extractor,  shook  out,  and  hung  on  a  suit- 
able wooden  horse.  Each  skin  is  then  separately  immersed 
in  a  vat  of  boiling  soapy  water,  and  when  sufficiently 
tucked,  the  skins  are  at  once  taken  to  a  drying  shed  heated 
up  to  a  temperature  of  120°  Fahr.  When  thoroughly  dry 
they  are  taken  to  the  stakers,  who  work  the  skins  out 
either  on  the  upright  or  by  the  crutch  stake,  when  they 
are  lightly  gone  over  again  on  the  emery  wheel.  The 
best  size  advised  for  this  purpose  is  a  wheel  of  about  two 
feet  nine  inches  wide  by  about  nine  inches  in  diameter, 
which  should  run  at  a  good  speed. 

Colouring.— Chamois  skins  are  usually  coloured  one  at 
a  time  by  spreading  them  on  a  convex  lead  or  zinc-covered 


CHAMOIS,   OR  OIL-LEATHER  MANUFACTURE.       363 

table.  The  colour  is  usually  of  a  mineral  base,  ochres 
and  umbers  being  often  used.  Of  late  years  more  or 
less  successful  attempts  have  been  made  to  use  coal-tar 
colours,  and  in  some  hands  good  results  are  said  to  have 
been  obtained.  The  usual  mineral  colour  is  mixed  to  a 
thick  consistency  in  a  sort  of  paint,  and  applied  evenly 
with  a  suitable  brush,  care  being  taken  to  keep  the 
colour  well  stirred. 

The  leather  is,  after  colouring,  then  dried  off  in  a 
hot  stove,  cooled  off  in  the  air,  and  again  staked.  It 
is  then  well  dusted  or  "  beaten  "  over  a  heavy  wooden 
stool  to  free  it  from  dust,  and  again  run  over  an  emery 
wheel,  care  being  taken  the  emery  used  is  fine,  so  that 
the  final  appearance  of  the  leather  may  be  soft  and 
velvety. 

The  skins  are  now  recoloured  and  dusted  as  before 
described,  and  in  some  cases  the  three  operations  involved 
are  again  carried  out. 

Dark  shades  are  often  obtained  on  chamois  leather  by 
running  the  skins  in  a  paddle  or  drum  in  a  weak  bark 
liquor  or  aniline  dye,  being  subsequently,  when  dry, 
topped  up  or  brushed  over  with  a  weak  solution  of  aniline 
colour. 

Deep  shades  of  brown  are  also  at  times  obtained  by 
hanging  the  skins  in  closed  chambers,  and  subjecting  the 
leather  to  the  action  of  ammonia  gas,  generated  by  first 
running  chloride  of  ammonia  solution  into  a  suitable 
vessel  in  the  chamber,  and,  later,  hot  lime  liquor  to 
liberate  the  ammonia. 

Buff  Leather. — Although  buff  leather  has  been  to 
some  extent  discarded  for  British  army  accoutrements, 
yet  a  fair  trade  is  still  done  in  this  material.  Hides 
of  a  suitable  class  are  used  for  its  manufacture,  the 
general  principle  being  much  the  same  as  in  chamois 
leather.  According  to  a  practical  writer  on  the  subject 
in  the  Leather  Trades  Eeview,  the  process  is  as 
follows : — 

Liming. — The  hides  are  put  into  old  or  weak  limes  at 
first,  handled  daily,  and  the  strength  of  limes  increased 


364  LEATHER  MANUFACTURE. 

for  about  ten  days,  when  it  will  be  found  the  hair  and 
cuticle  can  be  removed  by  pushing  over  beam  with 
unhairing  knife.  After  unhairing  they  are  put  into  fresh 
and  stronger  limes  for  a  few  days,  which  makes  the  hides 
firmer,  when  they  are  taken  to  either  splitting  or  frizing 
shop. 

If  split  only  a  thin  or  light  grain  is  taken  off,  or  if 
frized  the  grain  is  only  just  taken  off,  as  the  flesh  part  of 
hide  only  is  used  in  making  buff  or  oil  leather.  After 
frizing,  the  goods  are  again  returned  to  the  lime-pit  for  a 
short  time  until  ready  for  milling. 

Preparing  and  Milling. — The  hides  are  drawn  from 
the  pit,  and  in  place  of  being  drenched  are  hung  out  on 
lines  to  partially  dry  out  the  water  in  them,  by  action 
of  sun  and  air  in  summer,  or  in  winter  dried  in  a  warm 
atmosphere.  The  reason  they  are  not  drenched  is  be- 
cause a  firmer  leather  is  required.  When  sufficiently 
dry  they  are  taken  to  the  stocking  mill.  On  arrival 
at  the  mill  they  are  thrown  into  stocks  and  milled  for 
about  two  hours  to  distribute  the  moisture  evenly  and 
to  soften  them,  as  they  have  become  hard  or  horny  in 
drying. 

They  are  now  drawn  from  the  stocks  and  laid  out  to 
cool.  Meantime,  to  every  3  gallons  of  cod  oil,  1  quart  of 
freshly  sifted  slack-lime  is  added,  and  the  mixture  well 
stirred.  The  hides  are  now  thrown  into  the  stocks,  whilst 
another  man  sprinkles  them  with  the  mixture  of  oil  and 
lime.  After  the  stocks  or  fallers  are  full,  run  for  three  to 
four  hours,  when  it  will  be  found  the  hides  are  covered 
with  a  kind  of  lime  soap,  and  have  become  warm  by 
the  constant  beating. 

The  hides  are  now  drawn,  and  taken  and  hooked  in  a 
warm  stove  of  a  normal  temperature,  fitted  with  a  blast 
fan,  until  sufficiently  dry.  This  oiling  and  milling 
operation  is  repeated  several  days,  also  the  drying,  but 
gradually  increasing  the  warmth  of  stove  each  time,  until 
the  final  milling  preparatory  to  heating  off.  As  the 
hides  cannot  be  packed  into  tubs  or  bins  to  heat  off,  they 
are  hooked  in  a  very  hot  stove  with  a  large  coke  fire  in 


CHAMOIS,    OR   OIL-LEATHER  MANUFACTURE.        365 

the  centre,  or  heated  with  iron  furnace  pipes  laid  on 
bricks  about  twelve  inches  from  the  ground  and  all  round 
the  stove  inside,  the  furnace  door  being  let  into  wall  at 
exterior  of  wall  of  building.  The  latter  is  the  better  plan 
with  pipes  which  get  red- hot,  as  with  the  fire  in  the 
centre  of  the  stove  it  is  a  very  disagreeable  operation  to 
make  up  fires  on  account  of  heat  and  the  offensive, 
irritating  smell  (acroclin)  given  off  from  the  hides.  After 
the  hides  are  thoroughly  heated  off,  i.e.  when  they  are 
hard  and  dry  and  of  a  dirty  brown  colour,  they  are  ready 
for  washing. 

Scudding  and  Wash-honse. — The  hides  on  arrival  in 
the  wash-house  are  put  into  vats  containing  the  following 
solution :  To  every  hide  3  Ibs.  of  soda  ash  and  1  Ib.  of 
soda  crystals,  with  a  sufficiency  of  water  at  a  temperature 
of  112°  Fahr.  The  hides  are  laid  out  flat  in  this  vat  for 
twelve  to  fourteen  hours ;  they  are  then  drawn,  and  the 
scudder  takes  them  in  hand,  who  places  them  over  a  beam 
and  well  pushes  and  presses  them  to  remove  as  much 
grease  as  possible. 

They  are  now  returned  to  the  washers,  who  have 
heated  the  liquor  they  were  drawn  out  of,  and  also 
added  another  lot  of  soda  ash  and  soda  crystals.  This 
is  now  put  into  the  drum  (when  the  temperature  is 
about  120°  to  130°  Fahr.).  The  hides  are  now  thrown 
in  and  run  for  about  one  and  a  half  to  two  hours, 
when  they  are  drawn  and  the  liquor  run  off.  This 
liquor,  also  that  from  the  scudding  beam,  is  worth 
saving. 

Another  lot  of  liquor  is  then  made  up  as  follows :  \  Ib. 
of  soda  ash  and  \  Ib.  of  soda  crystals  with  sufficient 
water ;  raise  temperature  to  about  130°  Fahr.  The  hides 
are  now  drummed  in  this  liquor  for  about  one  and  a  half 
hours,  and  are  now  drawn  and  put  into  a  vat  containing 
a  fat-liquor  in  same  proportions  to  number  of  gallons  of 
water  as  in  treating  chamois  linings.  They  are  left  in 
this  liquor  about  an  hour,  and  are  taken  to  the  drying 
shed,  which  is  preferably  heated  with  warm  air  distributed 
with  a  blast  fan. 


366  LEATHER  MANUFACTURE. 

When  dry  they  are  ready  fur  bleaching  and  "tucking," 
which  is  carried  out  in  the  same  way  as  in  treating  chamois 
linings.  But  as  hides  cannot  be  handled  by  .grounders 
over  a  perch  with  a  moon-knife,  they  are  taken  by 
grounders  and  put  on  emery  wheels  or  special  hide 
machines  to  put  the  fine  smooth  face  on  them. 

Buck  Skin  Dressing. — Buck  or  deer  skins  are  limed 
exactly  as  hides,  first  for  twelve  to  fourteen  days  to 
remove  hair  and  cuticle.  After  sufficient  liming  they 
are  ready  for  drenching,  first  washing  in  clear  water 
to  rid  of  surplus  lime,  then  drenched  with  bran  liquor 
and  pressed  to  get  rid  of  surplus  liquor  in  the  same 
way  as  in  treating  chamois.  They  are  now  ready  for 
milling. 

Milling  or  Stocking. — The  milling  is  carried  out  on 
the  same  lines  as  in  milling  chamois  (no  lime  being 
added  to  the  oil),  but  the  milling  is  prolonged  as  the 
skins  have  the  grain  on,  having  been  neither  split  nor 
frized,  and  it  is  better,  even  after  buckskins  are  heated 
off,  to  let  them  lie  about  for  some  time  to  feed  on  the 
oil  before  taking  to  scudding  or  wash-house. 

Scudding  and  Wash-house. — The  skins  on  arrival  in 
wash-house  are  immersed  in  tubs  or  bins  of  hot  water 
placed  at  side  of  press,  and  are  now  pressed  in  the  usual 
way  (as  in  pressing  chamois).  On  removal  from  the  press 
they  are  immersed  in  tubs  holding  about  30  gallons,  a 
hot  liquor  having  been  made  up  with  soda  ash  and  lime 
at  a  temperature  of  about  112°  Fahr.  overnight.  They 
are  put  in  loosely,  and  are  left  in  this  liquor  till  the 
grain  begins  to  almost  rot,  when  the  skins  are  drawn  and 
placed  one  at  a  time  on  a  narrow  beam,  the  beam  not 
being  more  than  ten  to  twelve  inches  in  width,  when  the 
scudder  takes  a  very  keen  knife  and  pushes  the  grain  off, 
only  taking  very  narrow  strips  or  shavings  off  straight 
down  the  skin  from  neck  to  tail  or  vice  versa,  and 
frequently  shifting  the  skin;  hence  the  necessity  of  a 
narrow  beam.  After  scudding  they  are  ready  for  the 
final  washing.  The  scuddings  or  shavings  are  worth 
saving,  being  rich  in  grease. 


CHAMOIS,    OR  OIL-LEATHER  MANUFACTURE.        367 

The  skins,  having  been  immersed  in  strong  alkalies  in 
the  scudding  shop,  do  not  require  the  second  immersion, 
but  are  drummed  with  30  Ibs.  of  soda  ash  to  each  hundred 
skins  in  a  sufficiency  of  water  at  a  temperature  of  about 
120°  to  128°  Fahr.  After  thoroughly  washing  they  are 
fat-liquored,  as  in  treating  chamois. 

When  dry  they  are  finished  off  on  emery  wheels  or 
buck  machines  in  the  same  way  as  in  finishing  hides. 


CHAPTEK  XXX. 
CUEEYING. 

The  Scouring-house. — The  Shop. — The  Curriers'  Knife.— Currying  Kip 
Leathers. — Waxed  Kip  Butts. — Sorting  and  Bounding. — Soaking 
and  Softening. — Re-tanning. — Drum-stuffing.— Setting. — Finishing. 
— Stoning  and  Starching.  —  Graining.  —  Waxing.  —  Top-sizing.  — 
Currying  Satin  or  Glove  Shoe  Leather. — Soaking  and  Splitting. — 
Buffing. — Blacking  and  Setting. — Finishing  Satin  or  Glove  Leather. 
— Levant  Leather. — Soaking  and  Splitting.— Setting,  Buffing:,  and 
Embossing. — Blacking. — Seasoning  and  Glazing. — Oiling. — Curry- 
ing Various  Leathers.  Wax  Calf  Skins.— Calf  Skins  for  Memel.— 
High  Shoes,  Black  Grain. — Split  Cow-Hides  for  Brown  Bags. — 
Blocking  Boot-fronts. 

THE  art  of  currying  consists  in  dressing  skins,  after  they 
are  tanned,  for  the  purposes  of  the  boot  and  shoe  maker, 
coach  and  harness  maker,  saddler,  and  others,  by  which 
they  acquire  the  pliancy,  smoothness,  grain,  and  colour 
necessary  for  the  important  purposes  to  which  they  are 
to  be  applied.  The  operations  of  the  currier  are  chiefly 
mechanical,  and  form  a  distinct  branch  of  the  trade.  Many 
light  leather  manufacturers,  however,  combine  the  art  of 
currying  with  the  other  branches  of  their  business.  The 
curriers'  shop  requires  plenty  of  space,  subdivided  into 
many  compartments,  for  carrying  on  the  numerous  pro- 
cesses connected  with  the  trade.  If  possible,  the  lower 
part  of  the  building  should  be  devoted  to  those  operations 
in  which  large  quantities  of  water  are  required,  as  soaking, 
scouring,  and  cleansing  the  leather. 

The  Scouring-house  is  supplied  with  a  series  of  wide 
tubs,  in  which  the  leather  undergoes  a  preliminary  soak- 
ing ;  there  is  also  a  large,  flat,  and  smooth  stone,  about 
8  feet  long  by  4J  feet  wide,  supported  by  woodwork  or 
masonry,  upon  which  the  leather  is  scoured.  This  stone 
has  a  slight  inclination,  so  that  the  water  used  in  scouring 
may  freely  run  off  the  table  on  the  opposite  side  to  that  on 


CURRYING.  369 

which  the  workman  stands.  A  block  of  sandstone,  called 
the  rubstone,  from  2  to  3  feet  long  and  9  or  10  inches  wide, 
fixed  on  a  trestle,  is  employed  by  the  workmen  for  sharpen- 
ing their  various  tools.  A  finer  stone,  called  the  clearing- 
stone,  is  used  to  remove  the  marks  produced  by  the  coarser 
stone. 

The  Shop,  as  it  is  called,  is  a  light  and  generally  spacious 
apartment,  in  which  is  the  beam  (Fig.  50)  on  which  the 
leather  is  shaved.  The  beam  is 
constructed  of  a  stout  block  of 
wood,  upon  which  the  work- 
man stands,  and  into  one  end 
of  which  a  strong  plank  of 
hard  wood  is  firmly  secured, 
at  an  angle  of  80°  to  90°.  The 
working  beam  is  about  one 
foot  in  width,  and  its  height 
is  regulated  according  to  the 
height  of  the  workman,  each 
man  having  his  beam  adjusted 
to  suit  his  convenience.  On  the  face  of  this  upright,  as  it 
is  called,  a  piece  of  hard  and  perfectly  smooth  wood- 
generally  lignum  mice — is  attached,  and  which  agrees  with 
the  edge  of  the  knife  used  in  the  operation  of  shaving.  It 
is  of  the  utmost  importance  to  the  operator  that  his  knife 
and  beam  should  be  in  perfect  order,  otherwise  the  skins 
would  be  liable  to  injury  from  the  irregular  action  of  the 
tool. 

A  series  of  tables,  the  plane  surfaces  of  which  are 
nsually  made  from  mahogany  or  marble,  are  firmly 
fixed  to  the  floor  of  this  apartment,  near  the  windows, 
so  that  the  workmen  may  have  the  full  benefit  of 
the  light.  At  a  short  distance  from  each  table,  and 
behind  the  workman,  is  a  wooden  trestle,  across  which 
the  currier  throws  each  piece  of  leather  after  he 
has  worked  it  on  the  table  in  any  of  the  dressing  opera- 
tions. There  are  many  compartments  in  the  curry  ing- 
shop,  each  being  devoted  to  some  special  branch  of  the 
business,and  furnished  with  one  or  more  tables  and  trestles, 

2B 


370  LEATHER  MANUFACTURE. 

and  the  particular  tools  required  for  the  operations  to  be 
conducted  therein. 

The  Curriers1  Knife. — The  most  important  tool  is  the 
curriers'  knife  (Fig.  56),  which  consists  of  a  blade  of 
fine  steel,  tempered  in  a  peculiar  way, 
and  firmly  riveted  between  two  plates 
of  iron.  It  is  furnished  with  two 
handles,  one  of  which  is  horizontal  and 
the  other  vertical,  the  latter  being 
held  in  the  left  hand.  The  method  of 
giving  an  edge  to  this  tool,  which  is  remarkable,  is  thus 
described  by  Ure :  "  This  instrument  is  taken  to  the 
rubstone  and  ground  to  a  perfectly  sharp  edge  by  succes- 
sively rubbing  it  forward  and  backward,  care  being  taken 
to  keep  the  edge  true,  that  is  straight.  When  this  has 
been  satisfactorily  accomplished,  it  is  still  further  rubbed 
on  a  Scotch  or  Welsh  stone  called  the  clear  ing -stone,  until 
the  scratches  of  the  rubstone  disappear.  In  this  operation 
a  fine  thread  or  wire  forms  on  the  edges,  for  the  knife  has 
two  edges,  which  must  be  carefully  got  rid  of,  after  which 
it  is  wiped  dry  and  the  edges  greased  with  tallow  or  oil. 
The  workman  then  takes  a  strong  steel,  and  placing  him- 
self on  his  knees,  he  fixes  the  knife  with  the  straight 
handle  against  any  firm  body  and  the  cross  handle  between 
his  knees  ;  then  holding  the  steel  in  both  hands,  he  care- 
fully rubs  it  forward  and  backward  the  whole  length  of 
the  edge.  During  this  operation  the  knife  is  gradually 
raised  by  means  of  the  cross  handle  until  it  is  nearly  per- 
pendicular ;  by  this  means  the  edge  is  turned  completely 
over.  If  the  knife  is  not  well  tempered  the  edge  thus 
obtained  will  be  irregular  or  broken,  in  either  of  which 
cases  it  is  of  no  use  whatever.  To  keep  the  instrument  in 
proper  order  requires  great  skill  on  the  part  of  the  currier. 
The  edge  is  so  delicate  and  liable  to  injury 
that  it  cannot  be  used  more  than  a  minute 
or  two  without  losing  its  keenness.  To 
Flg'  57*  restore  this  a  very  carefully  prepared  small 
steel  is  used  (Fig.  57) ;  the  point  of  the  steel  is  first  run 
along  the  groove  and  then  along  the  outside  edge. 


CURRYING. 


371 


The  knife  is  used  as  shown  in  Fig.  f)8.  the  operation 
here  depicted  being  known  as  hand-shaving.  The 
process  is  now  often  done  by  machine,  which,  together 
with  the  modern  methods  of  currying,  are  now  dealt 
with. 


Fig.  58. 


Currying  Kip  Leathers.— Whilst  it  must  be  acknow- 
ledged the  old  methods  of  currying  produced  a  leather 
which  proved  serviceable  in  wear,  experience  has  shown 
that  its  manufacture  has  lately  produced  little  profit  to 
the  currier.  The  principles  underlying  the  treatment  of 
leather  by  the  currier  remain,  it  is  true,  much  the  same, 
but  machinery  has  displaced  hand  labour  to  a  great 
extent,  whilst  some  processes  have  either  been  dispensed 
with  altogether  or  very  much  shortened.  It  is  only  fair 


372  LEATHER  MANUFACTURE. 

to  say  that  the  advance  in  leather  manufacture  is  largely 
due  to  American  initiative  and  enterprise,  for  our  markets 
are  flooded  with  cheap- dressed  leather  from  the  United 
States,  whilst  American  machinery  is  being  sold  all  the 
world  over,  and  copied  by  competitors  everywhere. 

The  extent  of  the  American  trade  in  leather  is  clearly 
shown  by  a  reference  to  official  statistics,  and  it  speaks 
volumes  for  the  cheapness  and  excellence  of  the  trans- 
atlantic product,  if  we  remember  that  515,686  cwts.  of 
rough  and  dressed  leather  were  bought  in  1905  by  Great 
Britain  alone.  The  business  is  an  enormous  one,  and  it  is 
obvious  that,  with  such  competition  to  face,  the  British 
currier  has  had  to  get  into  line  with  the  American,  and  it 
is  proposed  to  here  briefly  describe  a  few  of  the  methods 
now  in  vogue  in  our  more  up-to-date  leather  works.  Need- 
less to  say,  they  vary  according  to  the  particular  market 
catered  for,  or  the  fancy  of  the  foreman  or  manufac- 
turer, but  the  principles  are  much  the  same,  whilst  the 
machinery  employed  is  similar  in  large  and  small  estab- 
lishments. As  a  chapter  is  devoted  elsewhere  to  the 
consideration  of  modern  leather  manufacturers'  machinery 
it  will  not  be  necessary  to  give  needless  details  here, 
beyond  just  the  points  required  to  make  matters  under- 
stood. Since  this  book  was  first  written,  the  causes  alluded 
to  above  and  the  introduction  and  popularity  of  the  chrome 
process  have  lessened  the  consumption  of  stout  upper 
leather  enormously.  In  fact,  many  go  so  far  as  to  say  that 
the  total  extinction  of  wax  leathers,  i.e.  leathers  finished 
black  on  the  flesh  side,  is  only  a  question  of  time ;  others, 
it  is  true,  do  not  hold  this  view,  for  wax  leathers  possess 
qualities  which  make  them  specially  suitable  for  the 
heavy  hard  wear  of  the  mechanic,  agriculturalist,  and 
other  wearers  who  require  a  boot  fairly  waterproof,  with 
a  certain  amount  of  porosity  and  at  a  low  price.  For 
these  reasons,  then,  waxed  leathers  are  still  popular,  but 
have  to  be  produced  at  a  much  lower  price  than  was 
formerly  the  case ;  and  it  is  proposed  in  this  chapter  to 
give  an  outline  of  the  processes  involved  in  the  currying 
of  kip  butts,  a  leather  which  has  even  now  a  large  sale. 


CURRYING.  373 

Kips,  it  should  be  said,  are  the  hides  of  the  native 
cattle  of  India;  these  are  imported  in  enormous  quan- 
tities both  in  the  raw  and  partly  tanned  condition ;  and 
to  a  large  extent  the  prosperity  of  Leeds  as  a  leather 
centre  has  been  built  up  on  the  successful  exploitation 
of  this  special  trade. 

Waxed  Kip  Butts. — It  will  be  more  convenient  for 
the  purposes  of  discussion  if  we  consider  the  kips  here 
alluded  to  are  those  which  are  bought  in  the  half- 
tanned  condition  by  the  currier.  This  leather  is  im- 
ported by  merchants  into  England,  and  at  intervals 
auction  sales  are  held  in  London,  a  sample  of  the 
goods  being  first  inspected  by  the  prospective  buyer. 
The  buying  is  mainly  done  by  the  buyers'  broker, 
whose  small  commission  is  more  than  saved  by  his 
expert  knowledge  placed  at  his  clients'  disposal,  whilst 
it  is  also  an  advantage  that  competitors  should  not 
know  what  other  buyers  are  obtaining.  The  tanned 
kips  are  selected  into  qualities  and  weights  and  care- 
fully catalogued,  and  the  buyer  naturally  selects  the 
various  "  marks  "  and  average  which  suits  his  particular 
trade.  The  larger  buyer  of  Indian  kips  also  purchases 
what  are  known  as  "original  bales"  direct  of  the  im- 
porters, but  as  these  hides  run  rather  irregular  in 
weight  and  substance,  it  is  more  economical  for  the 
smaller  currier  to  buy  the  selected  classes  at  the 
London  sales.  The  character  of  the  Indian  tannage 
varies  greatly  with  locality ;  for  instance,  Bombay 
kips  are  clean  and  well  got  up,  but  somewhat  spongy, 
whilst  Madras  are  hard,  and  often  badly  plastered  on 
the  flesh  side. 

Sorting  and  Bounding. — We  will  assume,  then,  the 
currier  has  obtained  his  kips,  and  that  they  are  in  his 
warehouse.  The  first  operation  is  to  sort  for  the  various 
purposes  required,  throwing  out  all  the  badly-flayed  and 
branded  kips  for  levant  or  lining  leathers,  or  any  purpose 
where  the  perfect  flesh  side  is  not  a  sine  qua  non.  After 
sorting,  the  kips  are  "  rounded "  or  cut  up  into  butts, 


374  LEATHER  MANUFACTURE. 

shoulders,  and  bellies,  the  butts,  as  a  rule,  being  the  only 
part  sufficiently  compact  in  the  fibre  to  make  waxed 
leather. 

Bounding  is  a  process  requiring  great  care  and 
judgment,  and  should  only  be  undertaken  by  a  man  of 
experience.  No  two  kips  are  exactly  alike  in  growth,  and 
it  is  easy  to  leave  an  inch  or  two  on  the  offal  which 
should  have  been  allowed  to  remain  on  the  butt,  or  vice 
versa.  A  rough  idea  will  be  gathered  of  the  usual  method 
followed  out  in  rounding  kips  by  an  examination  of  the 
diagram  shown  in  Fig.  14  (page  127). 

After  rounding  the  kips  the  butts  are  carefully 
weighed  and  put  up  into  "  packs "  or  "lots  "  of  about  five 
dozen.  It  is  needless  to  say  that  a  proper  stock  or  ware- 
house book  should  be  kept  of  all  lots  going  out,  and  that 
the  warehouseman  should,  on  giving  out  the  goods  to  the 
currier  for  dressing,  also  give  him  the  stock  number,  so 
that  track  may  be  kept  of  the  leather  right  through  the 
works  to  the  finishing  department. 

Soaking  and  Softening.— On  receiving  his  "lot,"  the 
currier  proceeds  to  soak  or  dampen  down  the  leather ;  it  is 
important  this  should  be  done  with  care,  otherwise  the 
subsequent  operation  of  shaving  is  rendered  very  difficult. 
The  leather  should  be  given  just  sufficient  water,  so  that 
on  doubling  back  the  grain  side,  the  moisture  just  oozes 
out.  In  very  cold  weather  it  is  an  advantage  to  soak  the 
harder  tannages  of  Indian  kips  in  warm  water.  The 
Madras  leather  especially  is  usually  undertanned, 
plastered  with  mud  or  grease  on  the  flesh  side,  and  so 
compressed  by  various  methods  that  it  is  often  difficult 
to  get  the  leather  to  take  the  water  at  all  unless  it  is 
warmed.  Of  course,  it  goes  without  saying  that  excessive 
heat  must  not  be  used,  otherwise  damage  to  the  leather 
is  the  result ;  but  it  is  a  pretty  safe  rule  that  if  the  work- 
man can  bear  his  hands  in  the  soak-tub,  the  water  is  not 
too  hot  for  the  leather. 

After  soaking,  the  leather  is  usually  allowed  to  lie  in 
pile  for  a  few  hours,  so  that  the  moisture  permeates 
evenly  through  the  fibre.  After  this  the  kips  are 


CURRYING.  375 

softened  in  a  drum-tumbler,  no  further  water  being 
added.  This  has  the  effect  of  taking  the  excessive  stiff- 
ness or  "  bone  "  out  of  the  leather,  thus  rendering  the 
subsequent  operation  of  shaving  much  easier. 

Before  shaving,  however,  the  butts  are  cut  down  the 
centre,  and  the  two  halves  plainly  marked  on  the  grain 
side  with  the  stock  number  and  the  "  fellow  mark."  This 
is  done  so  that  the  two  halves  may  be  matched  up  later 
on  in  the  currying  process. 

We  now  arrive  at  the  shaving  operation,  which  has 
been  fully  explained  at  the  opening  of  this  chapter. 
This  important  operation  is,  in  many  factories,  still 
done  by  hand,  i.e.  by  the  use  of  the  double-edged 
knife  pressed  smartly  with  a  downward  stroke  on  the 
flesh  side  of  the  leather  over  a  sloping  lignum  vitcc 
wood  block  (Fig.  58).  The  skilled  kip-butt  shaver  levels 
to  some  extent  the  inequalities  of  the  leather,  and  at 
the  same  time  endeavours  to  pare  out  the  veins,  flaws, 
and  other  defects  of  the  leather.  The  shaving  must  be 
free  from  knife-galls  and  scratches,  the  latter  especially 
showing  up  in  a  very  unsightly  manner  when  the  leather 
is  finished.  Generally  speaking,  the  aim  of  the  beams- 
man,  or  shaver,  should  be  to  produce  a  fine  and  even 
surface  at  the  least  possible  loss  of  weight  and  appear- 
ance. 

The  introduction  of  the  splitting,  and  later  the  shaving 
machine,  has,  however,  affected  the  art  of  the  old  crafts- 
man, and  it  seems  only  a  question  of  time  when  the  whole 
of  waxed  leather  will  be  shaved  by  mechanical  methods. 
Turning  first  to  the  splitting  machine  (see  Fig.  54,  page 
322,  and  Fig.  68,  page  412),  wonder  may  be  expressed  that 
this  easy  and  cheap  way  of  levelling  leather  has  not  long 
since  superseded  shaving  for  wax  leathers.  Experience 
has,  however,  taught  that  split  leather  does  not  produce 
so  fine  and  dense  a  fibre  as  that  obtained  by  hand  shaving. 
It  is  true,  kip  butts  are  sometimes  lightly  split,  but  these 
are  invariably  re-shaved,  or  "flatted,"  to  minimise  the 
effect  of  splitting  as  much  as  possible.  Still,  where 
excessive  fineness  of  face  is  not  an  absolute  necessity,  it 


376  LEATHER  MANUFACTURE. 

is  often  advantageous  and  economical  to  take  off  a  light 
split  from  the  rump  part  of  the  butt,  as  it  obviously  saves 
both  labour  and  material.  No  amount  of  work  and 
material  will,  however,  make  a  badly  split  kip  butt  equal 
in  appearance  and  value  to  the  shaved  article,  so  that  the 
operation,  if  done  at  all,  must  be  done  with  great  care 
and  judgment. 

As  may  be  gathered  from  the  chapter  on  leather- 
dressing  machinery,  a  good  deal  of  shaving  is  now  done 
by  machine.  In  fact,  practically  all  the  lighter  upper 
leathers  which  are  finished  on  the  grain  side  are  now 
shaved  in  this  manner,  but  it  is  still  an  open  question  in 
the  minds  of  experts  whether  there  is  any  great  saving  in 
the  use  of  the  machine  on  waxed  goods.  As  a  matter  of 
fact,  both  hand  and  machine  methods  are  in  use  by 
equally  progressive  concerns;  but  it  is  fair  to  say  that 
some  manufacturers  of  the  very  best  waxed  butts  still 
favour  the  ancient  method  of  hand-shaving.  The 
objections  urged  by  many  against  the  shaving  machine 
seem  to  be  much  the  same  as  those  experienced  by  split 
leathers.  Still,  the  difficulties  incidental  to  machine 
kip-butt  shaving  have  certainly  been  overcome  by  some 
curriers  who  vare  turning  out  a  good  article.  These 
leather  manufacturers  now  sort  out  the  various  weights, 
and  use  different  cutting  cylinders  to  suit  the  substances 
required,  and  apparently  the  finished  wax  leather  appears 
equal  in  every  respect  to  the  hand-shaved  article.  It 
seems,  therefore,  extremely  likely  that  it  is  only  a 
question  of  time  when  waxed  leather  as  a  whole  will  be 
shaved  by  machine,  for  continual  improvements  are  being 
added,  whilst  the  currier  has  profited  by  experience,  and 
year  by  year  more  fully  understands  the  capabilities  of 
such  profitable  mechanical  aids. 

As  shaving  machinery  is  more  fully  dealt  with  else- 
where, we  will  proceed  to  take  our  shaved  butts  to  the 
next  operation. 

Re-tanning. — As  the  butts  are  usually  very  under- 
tanned,  it  is  necessary  at  this  stage  to  rectify  this,  other- 
wise the  leather  will  not  take  up  sufficient  grease,  and  will 


CURRYING.  377 

be  deficient  in  solid  fibre.  Various  methods  are  in  use ; 
some  people  lay  the  goods  in  pits  with  a  strong  tanning 
liquor  for  a  few  weeks,  whilst  others  are  content  to  give 
them  a  brief  immersion  in  sumac  liquor,  or  an  hour  or  two 
in  a  good  strong  tan  liquor  in  a  drum-tumbler.  In  many 
large  works  the  butts  are  well  tumbled  in  a  mixed  tan  liquor 
composed  of  gambier  and  sumac,  and  perhaps  myrobalans, 
for  six  or  eight  hours.  After  this  they  are  then  again 
drummed  with  a  sumac  and  gambier  liquor  strengthened 
up  with  sufficient  good  oakwood  extract.  After  this 
second  drumming  the  butts  are  washed  through  a  warm 
sumac  liquor  to  brighten  up  the  colour,  and  are  then 
allowed  to  drain  for  a  few  hours,  when  they  are  hung  up 
to  dry.  Various  machines  are  in  use  for  ridding  the  butts 
of  moisture  before  drying.  In  some  works  the  hydraulic 
press  is  brought  into  requisition,  whilst  others  use  a  form 
of  squeezing  machine.  It  is  by  no  means  certain,  how- 
ever, that  these  are  an  advantage  for  the  purpose,  as  it 
is  thought  by  some  that  the  loss  of  certain  solid  matters 
in  the  tannin  leads  to  a  loss  of  weight  in  the  finished 
leather. 

In  the  olden  days  butts  were  after  re-tanning  scoured 
out  flesh  and  grain  on  the  slate  table  by  means  of 
sleaker  and  stock  stone,  when  they  were  "sammied," 
or  half-dried,  thoroughly  stretched  or  "set"  out  on  a 
wooden  or  marble  table,  and  stuffed  on  the  flesh  side  by 
applying  a  liberal  coat  of  dubbin  by  means  of  a  brush. 
The  butts  were  then  dried  out  slowly,  and  then  "tal- 
lowed" on  the  grain  side,  or,  in  non-technical  language, 
rubbed  over  on  the  grain  with  a  slight  coat  of  dubbin. 
Hand-stuffing  has,  however,  been  almost  entirely  super- 
seded by  a  method  known  as  drum-stuffing,  by  which 
melted  fats  are  mechanically  worked  into  the  leather  in 
the  tumbler.  This  is  really  the  most  important  modern 
development  of  the  curriers'  art,  and  as  such  warrants  a 
full  description  of  its  technique. 

D  nun-stuffing. — The  successful  application  of  grease 
to  leather  in  the  process  of  drum- stuffing  depends  upon  a 
variety  of  conditions,  and  much  money  has  been  lost 


378  LEATHER  MANUFACTURE. 

before  the  various  points  were  fully  understood.  Even 
now  burnt  leather  is  fairly  common,  although  the  intro- 
duction of  air-heated  tumblers  has  greatly  lessened  the 
risks  common  to  the  use  of  steam  for  the  purpose.  The 
modern  hot-air  drum  (see  Fig.  70)  is  now  often  fitted 
with  a  grease  melting  and  mixing  pan,  and  is  so  arranged 
that  the  melted  fats  are  fed  automatically  into  the  drum ; 
other  tumblers  are  fitted  with  both  steam  and  hot  air, 
the  former  being  useful  for  cleaning  purposes.  The  main 
advantage  about  the  hot-air  tumbler  is  that  it  can  be 
rapidly  heated  and  cooled,  the  latter  being  often  done  by 
injecting  cold  air. 

To  return,  however,  to  the  modus  operandi  of  drum- 
stuffing.  The  butts,  after  drying,  are  first  carefully 
weighed,  and  the  amount  of  grease  to  be  used  calculated 
on  a  percentage  of  this  dry  weight.  After  weighing  they 
are  damped  down  again ;  not  too  much  water  must  be 
given,  or  the  leather  will  fail  to  absorb  the  grease,  whilst 
if  the  butts  are  too  dry,  the  risk  of  burning  is  great. 
After  the  butts  are  quickly  dipped  in  the  water  they  are 
laid  in  pile  for  a  day  or  two  and  carefully  covered  with 
bagging.  This  has  the  effect  of  allowing  the  goods  to 
get  into  better  condition,  as  the  moisture  becomes  evenly 
distributed.  At  the  end  of  this  time  the  butts  are 
slightly  damped  in  the  dry  places  with  a  brush,  when 
they  are  ready  for  stuffing. 

A  good  deal  might  be  written  on  the  various  materials 
employed  in  drum-stuffing,  for  since  it  was  found  hard 
greases,  such  as  waxes,  stearines,  &c.,  produced  a  better 
looking  and  heavier  leather,  the  old- fashioned  tallow  and 
cod  oil  have  largely  dropped  out  of  the  currier's  list  of 
materials.  However,  it  will  be  sufficient  for  our  purpose 
to  give  one  or  two  representative  stuffing  mixtures  and 
their  method  of  application.  Generally  speaking,  the 
firmer  the  leather  is  required  the  greater  the  proportion 
of  hard  grease,  wax,  or  stearine  given  to  it.  In  America 
it  is  known  that  as  much  as  80  to  100  per  cent,  on  a  dry 
weight  of  the  leather  is  worked  in ;  but  English  curriers 
for  various  reasons  do  not,  as  a  rule,  obtain  such  results. 


CURRYING.  379 

In  drum-stuffing  the  drum  is  first  heated  up  to  the 
proper  temperature,  say,  about  130°  to  140°  Fahr.,  when 
the  condensed  steam  in  the  form  of  water  should  be 
run  off. 

In  the  older  form  of  drum  the  melted  grease  was  put 
in,  and  the  damp  leather  stacked  on  the  shelves,  when  the 
door  was  securely  fastened  and  the  drum  set  in  motion. 
Another  and  better  plan  is  to  put  the  butts  into  the 
heated  drum  and  allow  them  to  run  without  grease  for  a 
i'ew  minutes;  this  has  the  advantage  of  heating  the 
leather  through,  so  that  when  the  hot  grease  is  subse- 
quently added  it  does  not  coagulate  on  the  surface  of  the 
leather  and  thus  prevent  its  penetration.  In  the  more 
modern  form  the  grease  is  fed  through  the  axle  of  the 
drum  whilst  it  is  in  motion.  This  is  a  much  better 
arrangement,  as  it  prevents  any  single  piece  of  leather 
sticking  to  the  side  of  the  drum  and  thus  only  getting 
partially  stuffed.  Kip  butts  should  be  run  in  the  grease 
from  thirty  to  forty  minutes,  after  which  the  drum  door 
is  taken  off  and  replaced  by  an  iron  grill  or  grate,  and 
the  goods  allowed  to  run  another  half-hour  to  cool  down. 
It  is  best,  in  order  to  get  this  result,  to  run  the  goods  for 
a  few  minutes,  and  then  to  stop  the  drum  for  another 
short  period,  as  this  prevents  the  butts  from  being 
knocked  about  too  much,  and  thus  parting  with  a  portion 
of  the  grease. 

As  before  hinted,  no  two  curriers  use  precisely  the 
same  stuffing  mixture,  and  a  good  deal  of  unnecessary 
secrecy  is  observed  with  regard  to  their  composition.  In 
the  early  days,  when  drum-stuffing  was  introduced  from 
America,  nothing  but  cod  oil  and  tallow  was  used ;  now 
the  number  of  greases  used  is  legion.  Good  curriers 
claim  often  to  get  as  much  as  50  to  70  per  cent,  gain 
on  the  rough  weight  of  kip  butts  by  the  use  of  such 
materials  as  stearine,  degras,  or  sod  oil,  paraffin  wax,  and 
perhaps  a  little  resin.  The  first  mentioned  is,  of  course, 
the  chief  constituent,  and  splendid  results  are  obtained  in 
quality  and  weight  by  the  use  of  a  stearine  of  about 
100°  Fahr.  melting-point.  One  good  and  representative 


380  LEATHER  MANUFACTURE. 

stuffing  mixture  for  kip  butts  is  as  follows :  For  100  Ibs. 
of  dry  leather  take,  say,  10  gallons  of  stearine — or,  if 
tallow  is  used,  say,  50  per  cent,  more — 1  gallon  of  sod 
oil,  and  5  gallons  of  degras. 

It  is,  however,  of  little  practical  use  to  give  other 
formulas  for  stuffing  mixtures,  as  everything  depends 
upon  the  tannage  and  the  requirements  of  the  market. 
A  great  deal  must  be  left  to  the  judgment  of  the  in- 
dividual, but  if  the  rules  and  methods  given  are  carefully 
followed  out  no  loss  or  difficulty  should  be  experienced. 
Too  much  care  cannot  be  given  to  the  choice  of  good  and 
suitable  stuffing  materials,  and  experiments  should  be 
carried  out  slowly  at  first,  and  on  a  small  scale,  as  trouble 
with  leather  does  not  always  make  itself  manifest  until 
after  the  finished  leather  has  laid  in  stock  for  some  time. 

Setting. — This  is  an  operation  which  has  to  be  done 
quickly  and  thoroughly,  so  as  to  remove  all  stretch  and 
contracted  grain.  The  methods  in  vogue  differ  slightly, 
but  as  a  rule  the  grain  side  is  first  well  worked  out  on  a 
flat  table  with  a  stock  stone,  and  the  flesh  side  then  well 
"canked"  or  extended  with  a  suitable  steel  sleaker.  The 
grain  is  then  again  stoned  and  glassed  with  a  rounded 
glass  in  a  suitable  handle,  and  the  butts  hung  up  to  dry. 
Some  curriers  prefer  to  cank  them  first,  and  after  stoning 
the  grain  allow  the  butts  to  slightly  samm  or  dry,  and 
then  reset.  Some  lay  them  in  pile  between  the  two 
settings,  and  on  the  whole  the  best  results  perhaps  are 
obtained  this  way  if  the  damp  butts  do  not  lay  too  long 
and  thus  become  heated. 

In  any  event,  drum-stuffed  leather  should  not  lay 
about  in  the  air  long,  as  oxidation  is  apt  to  set  in  on  the 
exposed  surfaces  and  cause  unsightly  stains.  Machines 
are  now  being  used  for  kip  butt  setting,  and  once  the 
technical  difficulties  in  the  way  are  overcome,  it  is  only 
a  question  of  time  when  hand  setting  will  become 
extinct. 

Special  stress  has  been  laid  upon  the  drum-stuffing 
process  owing  to  its  revolutionary  character  as  compared 
with  the  old  hand  method,  and  also  to  the  difficulty  of 


CURRYING.  381 

obtaining  reliable  working  data  upon  it.  However, 
we  will  now  assume  our  kip  butts  have  been  carefully 
dried  in  the  sheds.  If  this  has  been  carried  out  with- 
out the  use  of  too  much  artificial  heat,  they  should 
be  of  a  good  colour  and  not  inclined  to  crack  on  the 
grain.  If  the  grease  has  done  its  work,  very  little  in 
the  way  of  rounding  or  "  tallowing  "  is  wanted,  although 
it  is  better  to  go  through  them  and  apply  a  little  dubbin 
where  it  is  required.  Some  curriers  lightly  brush  over 
the  flesh  side  with  dubbin,  and  allow  the  butts  to  lie  in 
pile  for  mellowing  purposes  for  about  a  month.  The 
butts  are  then  ready  for  the  final  operation  of  finishing, 
and  as  there  is  practically  no  grease  on  the  surface  of  the 
leather  the  old  process  of  "making  up" — necessary  to 
hand-stuffed  goods — may  be  dispensed  with. 

Finishing. — Whitening  is  the  first  operation,  and  it  is 
interesting  to  note  that  since  this  book  was  first  written  the 
whitening  sleaker  has  completely  ousted  the  light  shaving 
knife  for  that  purpose.  The  sleaker  is  much  more  con- 
venient to  use,  and  in  skilled  hands  produces  a  better  result, 
besides  taking  less  weight  off  the  leather.  The  work  is 
now  usually  done  on  a  glass  or  marble  table,  and  if  the 
butts  have  been  properly  shaved,  it  is  only  necessary  for  the 
workmen  to  just  skim  off  the  light  nap  or  fibre  which  has 
been  raised  by  the  previous  processes.  The  workman,  by 
pressing  the  leather  firmly  against  the  edge  of  the  table 
with  the  upper  part  of  his  legs,  proceeds  to  take  a  bold 
sweeping  stroke  straight  up  the  butt,  and  finishes  up  by 
lightly  skimming  over  towards  the  belly  edge. 

Whitening  is  greatly  facilitated  by  first  moistening 
the  surface  of  the  leather  by  a  weak  soap  solution  ; 
this  is  easily  applied  with  a  brush  or  sponge,  and  not 
only  greatly  assists  the  workman,  but  helps  to  form 
a  fine  and  close  surface.  Good  whitening  is  all- 
important,  and  the  work  should  be  free  from  scratches 
or  "  stabs,"  whilst  every  care  should  be  taken  to  avoid 
cutting  too  deeply  into  the  leather,  otherwise  coarseness 
of  fibre  is  unavoidable.  In  most  works  the  foreman 
carefully  looks  over  the  butts  after  whitening,  casting 


382  LEATHER  MANUFACTURE. 

out  any  which  are  badly  done.  Whitening  is  now  often 
done  by  machine,  and  good  results  are  obtained  by 
the  use  of  a  special  cylinder  on  the  shaving  machine. 
The  machine  shown  at  Fig.  72  is  also  used  for  the 
purpose. 

Stoning  and  Starching.— After  whitening,  the  butts 
are  stoned  and  sleaked  over  on  the  grain  side  to  remove 
any  adhering  grease,  &c.,  and  are  then  often  trimmed 
round  the  edges  with  a  sharp  knife  to  remove  rough 
edges.  The  currier  then  mates  each  half  butt  with  its 
proper  fellow  by  examining  the  marks  on  the  grain 
side  of  the  leather  made  before  shaving.  The  butts 
are  also  often  buffed  in  places  on  the  grain  side  if 
this  has  not  been  done  before  whitening;  this  is  a 
great  improvement  to  the  commoner  classes  of  goods, 
and  removes  scratches  and  broken  grain,  which,  if  left, 
look  very  unsightly.  The  butts  may  at  this  point  be 
given  a  weak  coat  of  some  mucilaginous  solution,  to 
which  is  added  a  little  colouring  mixture,  such  as  anatto 
or  some  suitable  aniline  dye.  This  operation  is  techni- 
cally termed  "starching,"  although  the  solution  used  is 
generally  composed  of  glue  and  water.  After  the  butts 
have  been  hung  up  to  dry,  they  are  ready  lor  graining. 

Graining. — This  process  is  fairly  simple  as  applied  to 
kip  butts  for  waxing,  for,  as  a  rule,  the  shoe  manufacturer 
requires  the  leather  firm,  so  that  it  stands  up  boldly  in 
the  boot.  In  most  works  graining  is  now  done  by  cross- 
ing and  recrossing  the  grain  of  the  leather  with  a  cork- 
covered  pommel,  the  same  tool  being  used  for  "  bruising  :' 
or  softening.  The  old  hand-graining  board  is  now  only 
used  for  the  lighter  kind  of  leathers,  such  as  sheep  and 
goat  skins,  a  heavier  and  much  more  serviceable  tool, 
called  the  "arm  board,"  being  used  for  graining  kip 
butts. 

Graining  is  so  well  understood  that  it  is  not  necessary 
to  again  take  up  space  by  describing  it;  the  primary 
idea  is  to  somewhat  soften  the  leather,  whilst  the  operator 
should  endeavour  also  to  develop  a  small  neat  figure, 
such  as  one  is  accustomed  to  see  on  grained  calf  skins. 


CURRYING.  383 

Naturally  the  workman  pays  most  attention  to  the  hard 
and  close  parts  of  the  butts,  as  the  less  pressure  put  upon 
the  belly  and  shoulder  parts  the  better,  owing  to  the 
comparative  looseness  of  the  fibre. 

At  this  point  the  leather  is  for  all  practical  purposes 
well  curried  and  ready  for  the  final  operation,  although 
some  curriers  prefer  to  apply  a  light  soap  solution,  which 
is  well  glassed  into  the  flesh  side  before  the  butts  are 
passed  on  to  the  waxing-room  for  the  final  blacking  and 
sizing.  In  this  state  the  leather  is  said  to  be  "in  the 
russet,"  and  it  is  in  this  condition  the  famous  French 
tannages  of  calf  skins  are  exported,  the  final  blacking 
being  put  on  in  England  or  elsewhere. 

Waxing. — Here,  again,  every  waxer  has  his  own  par- 
ticular methods  and  ideas;  the  principle  involved  is, 
however,  very  simple,  the  idea  being  to  produce  a  good 
and  deep  black  on  the  leather,  with  a  modified  gloss 
which  will  stand  the  somewhat  severe  handling  of  the 
shoe  manufacturer.  Some  waxers  use  a  sort  of  weak 
paint  composed  of  cod  oil  and  lamp-black,  to  which 
a  little  weak  sumac  liquor  is  added  to  facilitate  matters, 
whilst  others  prefer  a  soap  solution  as  a  medium  for 
the  colouring  matter.  The  soap  colour  is,  perhaps,  the 
most  useful,  as  it  helps  to  produce  the  great  desidera- 
tum of  the  currier — a  fine  and  smooth  surface.  With 
this  colour,  too,  there  is  no  danger  of  darkening  the 
leather,  as  is  often  the  case  when  oil  colour  is  used 
in  a  warm  room  by  a  waxer  who  is  anxious  to  show  a 
good  grain  of  weight.  But  whatever  colour  is  used 
only  enough  should  be  applied  with  a  brush  to  give  a 
good  black,  or  it  will  be  difficult  to  remove  the  excess 
of  "  smut "  or  solid  matter.  This  is  usually  done  by 
rubbing  over  the  leather  with  the  hand  or  a  suitable 
brush,  and  is  a  very  necessary  section  of  the  waxing 
operation.  After  smutting,  the  butts  are  usually  again 
glassed  and  are  then  bottom  sized,  i.e.  given  a  weak  coat 
of  a  properly  prepared  compound  which  is  well  rubbed 
in  with  a  glass  tool.  The  composition  of  bottom  sizes 
varies  greatly,  but  the  following  are  practical,  and  if 


3»4  LEATHER  MANUFACTURE. 

modified  to  suit  individual  cases  will  be  found  very 
useful : — 

1  Ib.  best  glue ; 

1   „  flour ; 

8  oz.  soft  soap ; 

4  „   sugar  of  lead. 

The  whole  of  the  materials  are  first  dissolved  in  seven  or 
eight  pints  of  logwood  liquor,  and  incorporated  by  stirring 
during  cooling. 

Another  bottom  size  is  prepared  thus : — 

10  pints  of  logwood  liquor ; 
1  Ib.  best  glue ; 
1   „   flour; 
^  „   soft  soap ; 
\  „   sulphate  of  copper  ("  bluestone  "). 

Whatever  bottom  size  is  used,  care  must  be  taken 
that  it  is  used  sufficiently  weak,  or  trouble  will  certainly 
arise  when  the  final  top-sizing  is  given  to  the  leather. 
In  practice  it  is  usual  to  first  try  both  sizes  experiment- 
ally, and  weaken  down  with  water  or  a  little  dubbin  if 
found  too  strong. 

Top-sizing — After  the  bottom  size  has  been  well 
glassed  in  and  allowed  to  dry,  the  butts  are  then  top- 
sized.  Only  sufficient  should  be  given  to  nicely  cover 
the  leather,  a  special  brush  being  used  for  the  purpose. 
Alter  the  composition  has  been  applied,  a  fine  smooth 
surface  is  obtained  by  finally  rubbing  the  still  damp  sur- 
face with  a  leather-covered  pad  or  a  bare  arm,  the  aim 
being  to  obliterate  the  brush  marks.  The  butts  are  then 
hung  up  in  a  heated  chamber  and  allowed  to  dry.  A  final 
glassing  and  oiling  with  warm  cod  oil  completes  the  pro- 
cess, and  if  the  methods  outlined  have  been  followed  out, 
a  saleable  article  should  be  the  result.  If  the  sizing  has 
been  well  done  with  suitable  materials,  the  surface  should 
improve  with  age,  whilst  the  size  should  become  tough, 


CURRYING.  385 

and  possess  a  "  bloom  "  which  is  appreciated  by  buyers 
of  this  kind  of  leather. 

Before  closing  this  chapter  it  may  be  as  well  to  give  a 
typical  top  size  for  waxed  leather.  This  may,  as  before 
hinted,  want  slight  modifications  to  suit  individual  re- 
quirements, but  it  will  be  found  a  good  working  formula, 
and  as  such  worthy  of  note  : — 

1  Ib.  best  glue ; 

10  pints  of  logwood  liquor  ; 

2  pints  cod  oil ; 
2  oz.  beeswax ; 

6  shoe-finishers'  heel-balls. 

The  glue  is  first  soaked  in  a  part  of  the  logwood  liquor 
and  then  slowly  dissolved  by  heat ;  the  other  ingredients 
are  also  dissolved  in  a  separate  vessel  and  added  to  the 
glue  solution ;  both  solutions  should,  of  course,  be  first 
carefully  strained  through  a  fine  muslin  cloth.  Care 
must  be  taken  to  keep  the  size  stirred  during  the  cooling 
process,  otherwise  the  final  result  will  be  unsatisfactory. 

Another  recipe :  1  Ib.  kid  clippings ;  7  pints  water ; 
1  Ib.  glue ;  \  Ib.  soft  soap ;  4  ozs.  beeswax ;  2  pints  cod 
oil ;  f  Ib.  tallow ;  4  ozs.  Venice  turps ;  2  ozs.  prepared 
asphaltum.  Prepare  and  mix  as  above. 

In  conclusion,  it  should  be  said  that  the  manufacture 
of  wax  kip  butts  has  been  gone  into  fairly  fully,  as  their 
manufacture  represents  the  modern  development  of  curry- 
ing, and  illustrates  better  than  any  other  leather  how 
old-fashioned  methods  have  been  grafted  on,  as  it  were, 
to  the  use  of  machinery  and  modern  methods.  The  trade 
is  still  a  very  large  one  in  these  goods,  and  as  the  leather 
possesses  qualities  which  are  difficult  to  obtain  in  other 
leather,  whilst  the  supply  of  raw  material  is  likely  to 
continue  fairly  abundant,  it  may  be  safely  assumed  that 
not  even  the  chrome  industry  will  ever  supplant  this 
valuable  section  of  the  orthodox  currier's  art. 

Currying  Satin  or  Glove  Shoe  Leather.  —  Under 
varipus  names  a  variety  of  most  useful  leathers  are  now 

2  c 


386  LEATHER  MANUFACTURE. 

finished  on  the  grain  side.  Satin  leather  has  long  been  in- 
cluded amongst  British  curried  leathers,  and  satin  calf  used 
to  be  highly  esteemed.  The  term  "  satin  "  is  sometimes 
applied  to  a  leather  finished  on  the  grain,  the  surface 
of  which  has  not  been  removed  or  buffed,  whilst  "  glove  " 
shoe  leather  is  usually  understood  to  mean  a  leather 
which  has  had  the  grain  removed :  both  terms  are,  how- 
ever, used  in  a  somewhat  arbitrary  manner.  It  is  claimed 
for  the  buffing  process  that  it  adds  to  the  wear  of  the 
leather,  as  the  hard  natural  outer  surface  of  the  dermis 
soon  becomes  hard,  and  ultimately  cracks.  On  the  other 
hand,  it  must  not  be  forgotten  that  buffing  immensely 
improves  the  grain  of  the  tanned  leather  by  obliterating 
barbed-wire  scratches,  frized  grain,  and  other  imper- 
fections which  curriers  are  painfully  familiar  with. 

It  may  be  mentioned  here  that  the  trade  in  glove  hide 
has  assumed  enormous  dimensions,  mainly  owing  to  the 
enterprise  of  the  Americans,  who,  by  the  employment  of 
machinery,  and  perhaps  a  highly  protected  home  market, 
have  been  enabled  to  sell  this  leather  at  a  very  low  price. 
The  American  tanner,  by  specialising  on.  side  leathers 
alone,  has  a  decided  advantage  over  his  European  com- 
petitor, who  is  perforce  obliged  to  handle  not  only  kips, 
but  shoulders  and  bellies  of  different  sizes  and  substances 
for  satin  purposes.  However,  a  good  trade  is  still  done  in 
grain  leathers,  and  in  the  following  summary  it  is  proposed 
to  give  an  outline  of  the  various  processes  employed, 
which,  although  varying  in  different  works,  yet  depend 
on  much  the  same  principles. 

Soaking  and  Splitting. — These  operations  are  carried 
out  in  precisely  the  same  way  as  in  the  case  of  kip  butt 
dressing  already  described.  In  the  case  of  the  lighter 
classes  of  kip  offal,  shaving  only  is  necessary,  which  may 
be  either  done  by  hand  or  machine.  It  might  here  be 
mentioned  that  thin  kip  shoulders  and  bellies  are  often 
dressed  and  blacked  on  the  grain  side,  and  are  commonly 
called  "  black  grain ; "  in  this  case,  however,  the  outer 
surface  of  the  grain  is  not  buffed  away  as  in  glove. 

As  a  rule,  it  is  only  the  stouter  and  rougher  classes  of 


CURRYING.  387 

hide  offal,  or  sides,  which  are  worked  up  into  satin  or 
glove,  and  as  the  leather  is  fall  in  substance,  it  is  well 
adapted  for  splitting,  whilst  as  the  flesh  split  is  also 
valuable,  it  is  obvious  the  saving  is  great.  As  before 
hinted,  successful  splitting  depends  upon  a  proper  pre- 
paration of  the  leather,  and  too  much  care  cannot  be 
taken  in  arriving  at  the  proper  amount  of  moisture  it 
should  contain,  or  in  the  careful  treatment  of  the  leather 
before  the  actual  splitting  commences.  It  is  usual  before 
splitting,  and  after  damping,  to  thoroughly  extend  the 
leather  by  means  of  a  suitable  machine;  this  has  the 
effect  of  removing  coarse  grain,  wrinkles,  &c.,  which 
would  leave  unsightly  marks  in  the  finished  leather. 
This  object  is  obtained  by  stoning,  or  "jacking,"  out  the 
grain  side  of  the  leather  on  a  machine  oi'  the  grasshopper 
type,  such  as  is  illustrated  in  Fig.  77.  Small  curriers 
usually  have  a  set  of  interchangeable  tools  for  this  piece 
of  plant,  and  amongst  them  a  stout  brass  or  stone  sleaker, 
which  is  very  useful  for  preparing  work  for  the  splitting 
machine. 

Much  might  be  written  on  proper  splitting,  but  no 
amount  of  instruction  will  possibly  make  an  expert 
splitter,  who,  by  the  way,  is  an  invaluable  adjunct  to  any 
leather  works.  Glove  leather  is  now  invariably  split  on 
the  band-knife  machine,  and  a  good  splitter  is  able  to  get 
his  leather  sufficiently  uniform  to  avoid  any  subsequent 
levelling  with  the  shaving  knife,  although  it  must  be 
acknowledged  that  for  some  classes  of  goods  this  latter 
operation  is  an  improvement.  Two  much  care  cannot  be 
taken  by  the  operative  in  splitting,  since  any  damage 
done  is  permanent.  He  should  frequently  examine  the 
leather  as  it  passes  through  the  machine,  and  immediately 
rectify  any  errors  in  substance.  The  knife  should  also 
be  kept  constantly  sharp,  and  the  bevel  most  suitable  to 
the  grade  of  goods  under  treatment  fully  kept  up.  Pre- 
cautions must  also  be  taken  to  guard  against  the  flying 
emery  dust  from  the  grinding  apparatus  coming  into  con- 
tact with  the  leather,  or  a  good  deal  of  discoloration  will 
be  the  result.  As  a  rule,  a  smart  boy  attends  the  splitter, 


388  LEATHER  MANUFACTURE. 

and  removes  the  leather  as  it  comes  through,  the  splitter 
carefully  feeding  the  leather  on  the  other  side.  In 
America  the  position  is  reversed,  the  chief  operative 
being  the  one  who  takes  the  leather  from  the  machine. 
In  America,  however,  several  splitting  machines  are 
under  the  charge  of  one  man,  who  is  really  responsible 
for  the  quality  of  the  enormous  quantity  of  work  turned 
off  by  the  machines.  Another  point  about  splitting 
worthy  of  note  is  the  necessity  for  a  sharp  removal  of  the 
goods  after  the  operation.  It  is  a  common  fault  to  see 
leather  being  left  about  near  the  machine  for  workmen 
to  walk  on,  or  to  catch  the  flying  particles  of  emery  from 
the  wheels.  The  machine,  too,  is  well  worth  attention  in 
the  way  of  extreme  cleanliness,  and  it  is  a  good  rule  to 
see  that  every  part  is  thoroughly  wiped  dry  and  rubbed 
with  an  oily  rag  after  the  day's  work. 

After  splitting,  kip  leathers  are  first  re-tanned  much 
in  the  same  fashion  as  described  in  the  previous  chapter. 
Hide  leathers,  being  fully  tanned,  do  not  require  this 
treatment,  and  are  usually  given  a  sumac  bath  in  the 
drum.  This  considerably  mellows  the  leather,  and  enables 
it  to  take  a  much  greater  quantity  of  grease  in  the  sub- 
sequent stuffing  processes  than  would  otherwise  be  the 
case.  After  sumacing,  the  goods  are  scoured  either  by 
hand  or  by  one  of  the  many  scouring  machines.  As  the 
leather  is  to  be  blacked  on  the  grain  side,  the  removal  of 
the  bloom  is  not  of  great  importance,  so  that  the  scouring 
may  be  pushed  forward  rapidly.  After  scouring,  the 
leather  is  either  taken  to  the  sheds  for  hand-stuffing,  or 
dried  out  if  the  process  is  to  be  done  by  the  drum.  Of 
late  years  the  former  process  has  almost  become  extinct 
in  the  larger  establishments,  owing  to  the  cost  and  the 
impossibility  of  getting  in  the  weight  as  compared  with 
drum-stuffing.  We  will  assume,  then,  drum-stuffing  is 
the  process  to  be  followed  out.  It  will  not  be  necessary 
to  again  go  into  details,  as  they  were  fully  described  in 
the  chapter  on  Butt-dressing,  but  it  cannot  be  too  often 
insisted  upon  that  the  greatest  care  is  necessary  in  the 
application  and  selection  of  the  various  greases  if  best 


CURRYING.  389 

results  are  to  be  looked  for.  Some  curriers  make  the 
mistake  of  supposing  that  any  old  grease  is  good  enough 
for  satin  or  glove  leather ;  but  it  is  hardly  necessary  to 
say  the  results  are  by  no  means  as  good  as  when  good 
fats,  such  as  tallow  or  stearine,  are  used.  The  amount  of 
grease  put  into  the  leather  varies  a  good  deal,  but  may 
be  probably  put  at  about  60  to  70  per  cent.,  calculated  on 
the  dry  weight  of  the  leather.  Of  course  the  whole  of  the 
melted  grease  put  into  the  stuffing-drum  is  not  absorbed, 
although  a  good  currier  loses  very  little.  The  gain  of 
weight  in  America  is  very  much  greater  than  in  England, 
as  much  as  90  to  100  per  cent,  being  obtained  on  the 
weight  of  the  dry  leather.  This  result  is,  however, 
largely  obtained  by  the  use  of  hard  stearines  and  waxes, 
whilst  the  fact  that  the  hemlock  tannage  is  a  good  grease 
absorbent  is  probably  an  important  factor  in  its  favour. 
In  stuffing  satin  leather  the  drum  is  heated  up  to  about 
140°  to  150°  Fahr.  before  the  leather  is  entered,  whilst  it 
takes  about  thirty  or  forty  minutes  for  the  melted  fats  to 
be  absorbed  by  the  leather.  After  cooling  down,  as 
already  explained,  the  leather  is  set.  In  many  places 
this  is  done  wholly  or  partially  by  machine,  although  if 
the  latter  plan  is  favoured,  the  work  has  to  be  gone  over 
again  by  hand  to  remove  the  marks  remaining.  The 
leather  has  to  be  in  any  case  very  fully  extended  both  on 
the  flesh  and  grain.  If  this  is  not  well  done,  the  grain  is 
coarse,  and  the  leather  will  probably  be  pipey  and  loose, 
to  say  nothing  of  the  greatly  increased  difficulty  which 
the  buffer  will  experience  in  the  removal  of  the  outer 
surface.  The  leather  is  then  dried  in  the  ordinary  way. 

Buffing. — Although  this  may  be  done  by  machine, 
yet  the  process  is  so  difficult  that  most  curriers  prefer 
hand-buffing.  Even  the  progressive  American  currier 
has  not  yet  fully  conquered  the  question  of  machine 
buffing,  although  the  problem  has  had  the  serious  atten- 
tion of  engineers  for  many  years  past.  Still,  for  some 
requirements  a  machine  does  the  work  well  enough,  and 
a  machine  of  the  type  described  in  the  chapter  on 
Machinery  (see  Fig.  72)  is  often  very  useful  for  the 


390  LEATHER  MANUFACTURE. 

purpose.  A  long  description  of  the  machine  is  not 
wanted  here,  but,  roughly,  it  consists  of  a  cylinder  con- 
taining an  arrangement  of  spiral  knives  fixed  at  the  end 
of  a  pendulum,  or  vibrating  arm,  the  whole  arrangement 
being  worked  over  a  sloping  table.  The  leather  under 
treatment  is  laid  over  the  sloping  table,  which  is  auto- 
matically raised  to  meet  the  action  of  the  cutting 
cylinder  by  means  of  a  foot  lever.  As  a  rule,  machine- 
buffed  leather  has  to  be  gone  over  again  by  hand,  as  the 
machine  is  apt  to  miss  the  thinner  parts  of  the  hide. 

In  hand-buffing  the  whitening  sleaker  is  used,  and 
only  expert  workmen  are  trusted  with  the  operation. 
The  grain  is  first  damped  with  a  soap  solution,  and  the 
buffer  takes  off  very  thin  shavings  from  the  surface. 
Great  care  should  be  taken  to  avoid  scratches,  stabs,  or 
"  run "  marks ;  otherwise  the  finished  leather  will  be 
unsightly  and  of  lower  value  than  would  be  the  case  with 
good  work. 

Blacking  and  Setting. — After  the  buffing  operation, 
leather  for  glove  or  satin  is  then  blacked.  Different 
curriers  have  different  methods  ;  some  mordant  the  grain 
with  a  logwood  solution,  and  apply  the  striking  iron 
liquor  at  once.  The  leather  is  then  well  set  out  on  flesh 
and  grain,  and  after  the  latter  had  been  dried,  a  solution 
of  some  filling  material  is  applied  with  a  soft  sponge. 
For  hide  sides  the  following  methods  may  be  taken  as 
fairly  representative,  whilst  it  also  obviates  to  some 
extent  the  tendency  toward  pipey  grain  before  alluded  to. 
Brush  over  the  grain  with  a  weak  solution  of  logwood 
liquor  (about  i  Ib.  to  the  gallon)  to  which  has  been  added 
a  little  ammonia.  Then  well  set  out  the  leather  on  the 
table,  which  has  previously  been  rubbed  over  with  tallow 
to  make  it  stick.  Care  should  be  taken  to  give  the  side 
a  good  pattern,  and  this  is  only  to  be  obtained  by  the 
workmen  using  the  setting  sleakers  by  following  the 
natural  lay  of  the  hide.  Ai'ter  this  setting,  the  leather 
is  again  washed  over  with  the  logwood  liquor,  when  a 
coat  of  some  suitable  ink  or  iron  liquor  is  given.  The 
sides  are  laid  by  in  a  pile,  and  are  then  thoroughly 


CURRYING.  391 

canked  on  the  flesh  side,  the  grain  being  this  time  stuck 
to  the  table  by  the  use  of  oil.  After  this  the  sides  are 
again  set  on  the  grain  side  to  the  table,  a  coat  of  dubbin 
being  first  brushed  on  to  the  latter.  After  a  further 
sleaking,  to  remove  surplus  particles,  followed  by  a 
glassing  or  pebbling,  a  coat  of  paste  or  bottom  size  is 
applied  with  a  sponge  or  brush.  Various  mixtures  are 
used,  but  the  following  will  give  excellent  results,  viz.  a 
quarter-pound  each  of  best  glue,  oil,  and  flour,  mixed 
in  about  two  quarts  of  hot  logwood  liquor.  This  is 
a  representative  formula,  but  different  tannages  require 
varied  pastes  and  sizes,  and  often  want  a  good  deal  of 
modification  to  suit  individual  requirements. 

Finishing  Satin  or  Glove  Leather. — After  drying  out, 
the  leather  is  now  whitened ;  in  some  places  this  opera- 
tion is  done  by  machines,  as  they  are  quicker  in  their 
action  than  hand  labour.  The  same  class  of  appliance  as 
that  spoken  of  for  buffing  does  whitening  fairly  well, 
although  opinions  as  to  its  merits  vary  considerably.  If 
the  leather  is  to  be  whitened  by  hand,  a  slight  skiving 
over  with  the  sleaker  is  sufficient,  as  in  this  case  it  is  only 
necessary  to  clean  the  flesh  side  for  appearance'  sake. 
When  the  leather  is  whitened  it  is  then  trimmed  at  the 
edges,  and  lightly  bruised  with  the  arm-board  to  soften 
it.  This  operation  is,  of  course,  done  from  the  grain  side 
so  as  to  avoid  raising  the  grain  ;  it  requires  care  and 
judgment,  and  very  little  pressure  should  be  given  to  the 
coarse  and  loose  part  of  the  hide.  Satin  is  then  again 
sleaked  down  on  the  grain  side  with  a  dull  sleaker  to 
remove  the  bruising  marks,  and  glassed  or  pebbled  as 
preferred.  The  leather  is  then  given  a  coat  of  finish  in  a 
warm  room  and  dried  out  very  thoroughly.  Some  people 
who  prefer  a  dull  finish  use  either  a  flour  or  gum  solution, 
a  few  drops  of  ammonia  being  added  to  it  if  any  difficulty 
is  experienced  in  its  application.  A  good  finish  may  be 
prepared  as  follows :  In  4  quarts  of  logwood  liquor  dis- 
solve 1 J  Ibs.  of  glue,  4  ozs.  of  brown  soap,  3  pints  of  cod 
oil,  and  2J  ozs.  of  beeswax.  This  is  applied  with  a  suitable 
pad  covered  with  cotton  wool,  over  which  is  tacked  a 


392  LEATHER  MANUFACTURE. 

piece  of  buffed  leather.  Extreme  care  must  be  taken  to 
avoid  marks  of  any  kind  in  the  application  of  the  finish, 
as  it  is  impossible  to  remove  them  later.  The  leather 
after  thoroughly  drying  is  now  again  glassed,  oiled  with 
warm  cod  oil,  again  hung  up  until  the  oil  has  penetrated, 
when  it  is  ready  for  the  finished-leather  store-room. 

Satin  or  glove  leathers,  it  is  true,  do  not  now  enjoy  the 
popularity  they  did  before  the  introduction  of  the  chrome 
tannage.  Still,  the  trade  is  yet  a  good  one ;  and  as  the 
leather  is  extremely  useful  for  such  work  as  the  cheaper 
grades  of  women's  and  children's  footwear,  it  is  very 
unlikely  it  will  ever  become  obsolete,  and  there  is  no 
reason,  if  the  above  directions  are  carefully  followed  out, 
why  the  reader  may  not  get  good  results  on  this  class  of 
leather,  even  if  he  has  not  been  accustomed  to  this  special 
work. 

Levant  Leather. — Until  the  advent  of  chrome  leather 
the  levant  trade  was  a  most  important  branch  of  the 
leather-dressing  industry,  and  even  now  kip  curriers  still 
find  it  a  useful  addition  to  their  business.  The  term 
"levant"  is  usually  applied  to  an  embossed  or  printed 
leather,  finished  on  the  grain  side  with  a  bright  surface, 
and  dressed  with  oil  only,  i.e.  not  stuffed  with  fats  and 
greases  as  in  the  case  of  waxed  leathers.  This  section 
of  leather  manufacture  provides  a  very  useful  outlet  for 
poor  goods  unsuitable  for  wax  and  satin,  and  very  little 
hand  labour  is  required  under  modern  conditions. 

Soaking  and  Splitting. — Taking  East  India  kips  as 
an  example,  the  process  is  as  follows :  They  are  first 
carefully  soaked  until  the  water  just  oozes  out  on  sharply 
pressing,  and  after  lying  in  pile  for  a  few  hours  they 
are  softened  by  a  short  drumming,  and  are  cut  straight 
down  the  centre  of  the  back. 

They  are  then  split  evenly  on  the  band-knife  machine, 
and  are  either  first  scoured  or  taken  away  for  retanning. 
This  is  invariably  done  in  the  drum,  a  mixture  of 
sumac,  myrobalan,  or  gambier  liquor  being  used,  often 
strengthened  with  a  certain  proportion  of  good  oakwood 
extract.  This  retanning  is  an  important  part  of  the 


CURRYING.  393 

levant  business,  as  India  kips  are  very  often  undertauned, 
and  if  this  is  not  reckoned  with,  the  finished  leather  will 
be  hard,  and  will  refuse  to  take  the  necessary  quantity 
of  oil  to  make  it  profitable. 

Setting,  Buffing,  and  Embossing. — After  drumming 
for  about  eight  hours,  either  drain  up  the  goods  thoroughly, 
press  or  squeeze  by  machine,  or  strike  them  out  on  the 
flesh  side.  Then  take  them  to  the  drying  sheds  and 
lightly  oil  with  linseed  oil  on  the  grain  side  and  hang 
up  to  samm.  They  are  then  well  set  by  means  of  a 
sharp  sleaker  on  the  flesh  side,  and  hung  up  and  dried 
out,  a  little  oil  being  used  to  stick  the  Rips  to  the 
table. 

When  fully  dry  go  carefully  over  the  grain  side,  and 
carefully  buff  all  broken  grain,  first  slightly  damping 
the  surface  with  a  sponge  and  sleaking  the  place  to  be 
buffed  well  first  with  a  dull  sleaker.  After  buffing 
where  necessary,  sort  the  kips  for  printing,  throwing 
all  those  inclined  to  be  "  pipey  "  or  coarse-grained  out 
for  the  heavier  style  of  print,  such  as  seal  or  big-star 
grain. 

The  embossing  or  printing  is  now  usually  done  by 
means  of  a  suitable  engraved  roller  (see  Figs.  81,  82),  the 
entire  side  being  subjected  to  a  fair  pressure  in  passing 
through  the  rollers.  A  better  impression  is  obtained 
if  the  leather  is  first  damped  slightly.  The  kips  are 
then  dried  out,  and  may  be  stored  in  this  condition  until 
ready  for  finishing. 

Blacking. — The  goods  are  now  dried  out  after  all  the 
pleats  made  by  the  machine  are  carefully  trimmed  out, 
or  remedied  as  far  as  possible  by  going  over  them  with 
a  small  hand  roller,  the  design  being  of  course  similar 
to  the  large  one  used  in  the  first  place.  After  embossing, 
the  next  process  is  the  blacking  operation.  This  is  done 
by  giving  the  grain  side  a  coat  of  logwood  decoction, 
and  subsequently  another  coat  of  levant  ink,  care  being 
taken  to  keep  the  flesh  side  as  clean  as  possible.  When 
trimmed  the  kips  should  be  well  softened  and  grained: 
This  is  now  almost  always  done  by  the  boarding  machine, 


394  LEATHER  MANUFACTURE. 

the  bulk  of  the  work  being  done  to  the  flesh  side  to 
prevent  piping  (Fig.  71). 

Seasoning  and  Glazing. — After  this  softening  the 
goods  are  seasoned,  care  being  taken  to  have  the  season- 
ing material  well  brushed  into  the  grain.  A  suitable 
seasoning  is  composed  as  follows :  6  pints  of  bullock's 
blood ;  4  pints  of  logwood  solution ;  2  pints  of  blue  archil 
solution,  and  £  pint  of  spirit  of  wine.  When  the  season 
has  well  dried  into  the  leather,  have  the  kips  again  well 
grained,  taking  special  care  that  the  design  is  made  as 
perfect  as  possible  and  that  "  piping  "  is  avoided. 

A  second  seasoning  is  then  applied  composed  of  the 
following  ingredients:  7  pints  of  blood;  4  pints  of 
logwood;  2  pints  of  new  milk;  1  pint  of  archil  liquor; 
^  pint  of  spirit  of  wine  ;  and  2  ozs.  of  burnt  sugar. 

After  the  goods  have  been  well  dried  they  are  usually 
fluffed  on  an  emery  wheel  to  clean  the  flesh,  and  are 
then  ready  for  glazing.  It  is  best  before  taking  them 
to  the  machine  to  slightly  wipe  them  over  with  a  rag 
dipped  in  linseed  oil,  as  it  helps  to  prevent  dragging 
or  scratching  under  the  pressure  of  the  glazing-glass 
or  agate.  The  machines  in  use  are  many,  but  those  of 
the  type  shown  in  Figs.  77  and  78  are  representative. 
After  glazing,  the  goods  are  again  carefully  grained, 
the  pattern  being  carefully  preserved.  This  requires  a 
good  operator,  as  it  is  impossible  to  rectify  mistakes 
made  in  this  final  graining. 

Oiling. — A  final  oiling  now  completes  the  process. 
This  is  applied  with  a  suitable  wad  or  flannel  rag,  the 
oil  being  warmed  and  spread  evenly  over  the  surface 
of  the  grain.  Linseed  or  mineral  oil  is  used  for  the 
purpose,  according  to  the  quality  of  the  goods.  Some- 
times a  mixture  of  both  is  given,  whilst  others  oil  off 
solely  with  the  cheap  mineral  product. 

Care  should  be  shown  in  the  oiling,  otherwise,  if  too 
much  is  given,  it  will  penetrate  to  the  flesh  side,  and 
spoil  the  appearance  of  the  finished  leather.  The  kip 
sides  are  now  sorted  into  qualities  and  substances,  and 
are  ready  for  the  shoe  manufacturer. 


CURR  YIXG,  395 

Currying  Various  Leathers.  Wax  Calf  Skins. — From 
an  interesting  series  of  articles  upon  currying  which 
appeared  some  years  ago  in  a  technical  journal,  now 
extinct,  we  make  the  following  extracts,  as  they  illus- 
trate the  difference  between  the  new  methods  described 
in  this  chapter,  and  the  old  ideas  on  which  they  are 
based : — 

"  Calf  skins  of  various  weights  (tanned),  from  2J  Ibs.  to  8 
or  9  Ibs.  each,  are  curried  for  shoe  purposes.  Light  skins 
should  not  be  shaved  so  much  as  heavy  ones ;  the  flesh 
should  merely  be  taken  off  and  the  veins  taken  out,  so 
that  they  may  be  level  in  the  butt  part,  being  first  of  all 
shaved  over ;  they  do  riot  require  flattening  except  they 
are  lumpy — that  is,  thicker  in  one  part  than  another. 
After  they  are  shaved,  scour,  flesh,  and  grain,  give  them  a 
good  sumacing,  and  let  them  lie  for  a  day  or  two.  Warm 
the  liquor  before  they  are  sleeked  out  of  that ;  stiffen  them 
11  little  in  the  shed.  If  they  are  not  very  coarse  in  the 
grain  they  need  not  be  set  on  the  grain  at  all,  as  it  will 
be  found  that  it  renders  them  much  softer  and  more  after 
the  style  of  French  skins.  Before  stuffing,  put  a  little  oil 
or  dubbin  on  the  grain,  turn  over,  and  sleek  them  on  the 
flesh,  then  put  the  dubbin  on  the  flesh  and  hang  on  two 
loops  in  the  shed  to  dry.  When  dry,  take  down  and  put 
a  little  dubbin  on  the  grain,  commonly  called  *  tallowing,' 
and  lay  them  aside  for  a  few  days.  Heavy  skins  require 
more  shaving  than  light  ones,  and  therefore  take  more 
dubbin.  After  they  have  lain  by,  if  heavy  skins,  slightly 
raise  the  grain  with  a  toothboard  or  cork.  Sleek  the 
grease  off  the  flesh  and  grain,  and  whiten  them  with  a 
turned  sleeker  or  knife,  whichever  the  dresser  uses  best. 
Bruise  on  the  flesh  and  grain  up,  then  wax  them.  The 
process  of  waxing  is  to  colour  on  the  flesh — that  is,  to  put 
black  on  the  flesh  (lampblack  and  oil).  Now  glass  down 
on  the  flesh,  and  size  on  the  same  side ;  hang  up  for  the 
size  to  get  quite  dry,  then  glass  on  the  same  side. 

Calf  Skins  for  Memel  weigh  from  30  to  40  Ibs.  per 
dozen.  These  are  shaved  level,  scoured  flesh,  and  grain, 
care  being  taken  not  to  injure  or  break  the  grain ;  they  do 


396  LEATHER  MANUFACTURE. 

not  require  much  suinacing,  if  well  tanned.  Sleek  out  on 
the  grain  and  hang  in  the  shed  to  samm ;  when  stiff 
enough,  set  them  on  the  grain,  and  print  them  with  a 
memel  or  straight-grain  roller.  Oil  on  the  grain,  turn 
over,  and  lay  flat  on  the  table ;  but  do  not  set  them  on  it. 
Stuff  them  on  the  flesh ;  but  they  do  not  require  so  much 
stuffing  or  dubbin  as  wax  leather ;  now  hang  up  to  dry. 
Some  persons  have  them  printed  after  they  are  blacked, 
others  will  not  have  them  printed  at  all  when  dry.  Next 
take  them  down  and  black  on  the  grain  side,  and  size ; 
when  well  hardened,  slightly  grain  up,  and  put  them 
in  the  stove  or  drying-room ;  when  dry,  clean  the  flesh 
side,  and  finish  graining,  then  oil  with  linseed  oil,  when 
they  are  ready  to  cut  up. 

High  Slices,  Black  Grain.— These  are  mostly  cut  from 
the  best  part  of  the  hide,  free  from  cuts  on  the  grain  side, 
and  must  not  be  shaved  so  low  at  the  bottom  part.  Scour 
flesh  and  grain,  compo  if  desired,  as  it  renders  them  soft 
and  pliable,  and  they  take  more  stuff;  now  hang  in  the 
shed  to  samm  ;  set  on  the  grain,  if  required,  oil,  and  print 
before  stuffing,  with  a  straight  or  cross-grained  roller. 
Turn  over  and  stuff  on  the  flesh  side ;  they  will  generally 
take  twice  as  much  stuff  as  wax  legs,  in  fact  you  cannot 
give  them  too  much.  Now  hang  in  the  shed  to  dry,  and 
when  dry,  black  on  the  grain  and  oil.  When  the  oil  is 
absorbed,  raise  the  print  with  a  cork  or  toothboard,  then 
hang  up  in  the  drying-shed ;  before  doing  so,  however, 
they  should  have  a  coat  of  dubbin  on  the  grain,  if  they 
have  lain  by  for  some  time.  Sleek  the  grease  off  the 
flesh,  bruise  the  flesh,  grain  up  and  give  them  a  good  coat 
of  clear  oil  on  the  same  side :  they  are  then  fit  for  use. 

Split  Cow-Hides  for  Brown  Bags. — These  are  shaved 
lightly  on  the  flesh  side  until  they  are  level ;  they  are 
then  scoured,  flesh  and  grain,  and  sumached ;  next  sleeked 
out  of  the  sumac ;  then  put  into  the  shed  to  samm,  and 
when  stiff  enough  are  printed  on  the  grain.  Stiff  tallow 
dubbin  is  laid  over  the  grain,  buck  or  deer  tallow  being 
preferred.  Stuff  on  the  flesh  if  desired,  otherwise  slightly 
glass  down  on  the  flesh,  and  hang  up  to  dry.  After 


CURRYING. 


397 


drying,  raise  the  print,  and  bruise  on  the  flesh.  See  that 
this  side  is  free  from  grease,  then  glass  the  same  side,  and 
brush  the  grain  with  a  good  hair-brush,  when  they  are 
ready  for  sale." 

Blocking  Boot-fronts. — This  operation,  which  was  for- 
merly conducted  by  the  bootmaker,  sometimes  forms  a 


Fig.  59. 

branch   of    the   currier's   business.      For   the   following 
description  of  the  block  ing-machine,  and  the  method  of 


Fig.  60. 

working  it,  we  are  indebted  to  Ure's  "  Dictionary  of  Arts, 
Manufactures,"  &c.  The  leather,  being  dressed  as  before 
described,  is  cut  out  as  at  a,  Fig.  59,  and  when  folded  or 
doubled,  appears  as  at  6. 

In  Fig.  60,  1  1  1  is  a  strong  frame  of  woodwork  ;  2 


39^  LEATHER  MANUFACTURE. 

represents  a  pair  of  cheeks,  strongly  fastened  in  the 
frame,  and  regulated  to  a  distance  by  a  screw.  These 
cheeks  are  lined  with  zinc.  3  is  a  strong  plate  of  metal, 
the  angle  at  3  corresponding  exactly  with  the  angle  of 
the  cheeks ;  the  ends  of  this  plate  are  fixed  in  movable 
plates  passing  down  the  columns  1  1 ;  4  is  a  handle  by 
which  the  instrument  is  worked,  and  which,  by  cog- 
wheels acting  on  the  movable  plate,  brings  3  down- 
wards. The  front  a  is  laid,  after  a  thorough  soaking  in 
water,  over  the  cheeks  2 ;  the  handle  being  turned,  3 
comes  down  upon  the  front,  and  forces  it  through  the 
small  opening  between  the  cheeks,  and  when  brought  out 
below  the  cheeks  it  has  the  appearance  given  at  c. 
The  plate  3,  having  carried  the  front  between  the  cheeks, 


FIG.  61.  FIG,  62. 

is  removed  (below),  and  the  weight  5  assists  in  bring- 
ing the  perpendicular  movable  plates  to  their  place, 
when  3  is  again  put  in  position,  and  thus  the  operation 
is  rapidly  carried  on.  After  this  the  fronts  are  regularly 
placed  on  a  block,  being  forced  into  position  by  an  instru- 
ment called  a  flounder  (Fig.  61),  and  tacked  to  their 
place.  After  this  they  are  slightly  oiled  and  dried.  Some 
ingenious  methods  have  been  adopted  for  softening  fronts 
so  as  not  to  disturb  the  Hocking.  They  are  whitened  on 
a  very  sloping  beam  or  horse  (Fig.  62),  which  enables 
the  workman  to  hold  them  better  than  he  could  on  the 
common  beam.  They  are  again  blocked  by  the  waxer, 
and  when  these  processes  are  carefully  performed  much 
trouble  is  saved  to  the  bootmaker. 


CHAPTER  XXXI. 

MACHINERY  EMPLOYED  IN  LEATHER 
MANUFACTURE. 

•'Stocking"  or  Softening  Machines. — Depilation  and  Fleshing  Plant. — 
Machines  for  Crushing  and  Grinding  Tanning  Materials. — Solo 
Leather  Finishing  Machinery. — Leather  Dressing  Machinery. — 
Scouring  and  Setting  Machinery.  —  Embossing  and  Softening 
Machinery. — Tanning  and  Stuffing  Drums. — "  Boarding  "  and  Soften- 
ing Machines. — Machinery  used  in  Chrome  Leather  Manufacture. — 
Machinery  used  in  the  Beam  House. — Finishing  Machinery  for 
Chrome  Work. 

DURING  the  past  few  years  the  use  of  mechanical  aids  has 
greatly  increased  in  every  department  of  the  leather 
trade.  True,  the  British  tanner  is  not  so  enthusiastic 
over  their  adoption  as  his  hustling  American  rival,  as  he 
has  to  deal  with  smaller  quantities  and  more  varied  lines 
of  goods ;  in  a  word,  he  has  not  the  opportunity  of  speciali- 
sation common  to  the  United  States.  On  the  other  hand, 
it  must  be  admitted  that  many  of  the  best  machines  had 
their  origin  on  the  other  side  of  the  Atlantic,  and  that 
they  have  only  been  adopted  in  other  parts  after  the 
progressive  American  had,  by  long  and  costly  experiment, 
proved  their  utility.  The  inventiveness  of  the  native 
American,  and  the  readiness  of  tanners  to  take  up  new 
ideas,  have  been  important  factors  ;  in  short,  a  variety  of 
causes  have  favoured  the  transatlantic  machinist,  the 
cost  of  skilled  labour  being,  perhaps,  amongst  the  most 
important. 

Of  late  years,  however,  a  good  deal  of  tanners'  machinery 
has  been  made  in  England  and  the  Continent,  and  there 
is  now  very  little  to  choose  in  quality  or  price  between 


400  LEATHER  MANUFACTURE. 

the  various  makes,  although  the  Americans  admittedly 
do  not  put  so  great  an  amount  of  finish  into  their  work. 
Naturally,  the  greatest  chance  for  the  leather  trades' 
engineer  has  been  in  the  direction  of  the  lighter  leathers, 
and  there  is  no  doubt  but  that  the  introduction  and 
exploitation  of  chrome  leathers  has  proved  his  great 
opportunity. 

The  cost  of  machines  suitable  for  sole  leather  tanners 
and  their  enormous  capacity  have  made  it  somewhat 
difficult  to  successfully  push  this  class  of  plant.  Until 
quite  within  recent  times  many  of  the  sole  tanneries 
have  been  on  a  very  small  scale  ;  modern  competition  is, 
however,  gradually  proving  too  strong  for  them,  and  the 
industry  is  drifting  into  larger  hands.  Stronger  tanning 
materials  have  also  taken  the  place  of  the  British  oak- 
bark,  and  to-day  there  are  many  large  tanneries  in  the 
Warrington  and  Liverpool  districts  with  a  capacity  of 
one  to  three  thousand  hides  per  week.  Such  yards  as 
these  can,  of  course,  profitably  employ  machinery,  and 
the  persistence  of  the  leather  trades'  engineer  is  thus 
slowly,  but  surely,  having  its  reward.  It  will  be  im- 
possible, in  the  space  at  our  disposal,  to  explain  or 
enumerate  all  the  various  machines  now  employed  in 
light  and  heavy  leather  manufacture,  but  enough  will 
be  said  to  enable  the  reader  to  become  au  courant  with 
the  most  important  developments  introduced  within  the 
past  few  years. 


MACHINERY  USED  IN  SOLE  LEATHER  TANNING. 

"  Stocking "  or  Softening  Machines.  —  The  old- 
fashioned  plan  for  softening  the  soaked  hide  was  to 
"  break  "  it  over  on  the  half-round  tanner's  beam  with  a 
blunt  knife.  This  plan  is  still  followed  out  in  small 
yards,  and  in  countries  where  labour  is  cheap  and 
plentiful.  This  method  is  now  supplemented  or  super- 
seded by  the  use  of  the  "  stocks."  This  machine  consists 
of  a  metallic  box,  in  which  rise  and  fall  two  heavy 


MACHINERY  IN  LEATHER  MANUFACTURE.        40! 

hammers,  raised  alternately  by  projections  in  a  revolving 
wheel.  The  action  is  very  effective,  being  a  sort  of 
kneading  or  pounding,  and  the  most  obstinate  hides  give 
way  to  the  treatment.  The  duration  of  stocking  varies 
from  ten  minutes  to  half  an  hour.  The  ordinary  form 
of  stocks  in  use  for  softening  Indian  kips,  China,  "  flint," 
and  other  stubborn  hides  is  shown  in  Fig.  6,  p.  111. 
A  more  modern  device,  which  claims  some  advantages, 


Fig.  63. 

is  the  American  double-shover,  the  principle  of  which 
is  shown  in  Fig.  63. 

There  are  other  forms  of  stocks  upon  the  market,  but 
the  above  two  examples  give  a  fairly  accurate  impression 
of  the  main  principle  involved. 

On  the  Continent  of  Europe  a  machine  of  a  somewhat 
different  type  is  used,  which  possesses  the  advantage  of 
being  lighter  in  its  action  upon  the  thinner  parts  of  the 
hide.  The  idea  is  simple,  being  that  of  a  pair  of  rollers 
pressed  together  by  a  spring.  One  roller  is  studded  with 
blunt  pegs,  which  corresponds  to  grooves  in  the  other, 

2  D 


402  LEATHER  MANUFACTURE. 

and  so  arranged  that  the  hide  is  subjected  to  a  very 
thorough  kneading. 

The  method  of  stocking  and  softening  varies  very 
much  in  nearly  all  yards,  but  in  spite  of  the  march  of 
engineering  improvements,  the  stocks  remain  much  the 
same  in  principle  as  in  the  day  when  the  tanner  probably 
borrowed  the  idea  from  his  cloth-making  confrere.  For 
the  lighter  kind  of  skins,  drum  tumblers  are  effective 
for  softening;  but  it  will  be  more  convenient  to  deal 
with  light  leather  machinery  under  a  distinct  heading. 

Depilatiou  and  Fleshing  Plant. — After  the  preliminary 
softening  and  cleaning,  the  hides  intended  for  sole  leather 
are  then  ready  for  some  process  which  will  swell  the  pelt 
and  loosen  the  hair  so  that  it  can  be  easily  removed. 
The  most  common  method  is  to  immerse  the  pelt  in  a 
lime  solution,  which  not  only  loosens  the  hair  and  swells 
the  hide,  but  converts  the  fat  it  contains  into  a  lime  soap, 
at  the  same  time  so  loosening  the  cutaneous  tissue  that 
the  surplus  flesh  is  easily  worked  off.  Other  methods  of 
unhairing  depend  upon  the  use  of  sulphides,  and  putre- 
faction, technically  termed  "sweating."  By  whatever 
means,  however,  the  hair  is  loosened,  it  is  usually  re- 
moved by  hand,  as  the  labour  involved  is  not  costly; 
and  so  far  attempts  to  do  the  work  by  machine — at  any 
rate  on  the  heavier  hides — have  not  been  particularly 
successful,  owing  mainly  to  the  fact  that  it  is  generally 
necessary  to  supplement  the  machine  work  by  hand 
labour,  as  it  is  oiten  difficult  to  remove  short  hair,  or 
that  from  patches  where  the  pelt  has  been  insufficiently 
softened.  Much,  however,  depends  upon  the  require- 
ments of  the  market  and  the  output  of  the  yard.  The 
principle  of  many  of  the  various  unhairing  machines 
consists  of  a  rapidly  involving  cylinder,  fitted  with 
spiral  blunt  knives,  working  over  another  rubber-covered 
cylinder,  the  hide  being  fed  or  introduced  between  the 
two.  The  Turner  Tanning  Machinery  Co.,  Peabody, 
U.S.A.,  and  Leicester,  Eng.,  have  a  machine  upon  the 
market  large  enough  for  sides  and  whole  hides,  which 
is  shown  in  Fig.  64.  It  is  claimed  by  the  inventors 


404  LEATHER  MANUFACTURE. 

of  this  machine  that  many  hundreds  of  them  are  in 
operation  in  the  largest  tanneries  in  all  parts  of  the 
world  for  unhairing,  fleshing,  and  general  work  in  the 
beam  house.  The  cost  of  big  machinery  is  naturally 
great,  and  the  expenses  of  running  fairly  so ;  it  is  there- 
fore obvious  that  an  appliance  of  this  kind  is  only 
profitable  in  large  tanneries. 

Much  the  same  criticism  might  apply  to  the  operation 
of  fleshing,  which  invariably  follows  unhairing.  It  is 
questionable  whether  any  machine  has  yet  been  invented 
which  will  give  cheaper  or  better  results  on  hides  than  the 
old  plan  of  paring  off  the  loose  flesh  by  the  use  of  a  sharp 
knife  on  the  half-round  beam.  Machinery,  it  is  true,  does 
the  work  rapidly,  but  a  certain  amount  of  damage  is  in- 
evitable, whilst  it  is  difficult  to  do  the  work  uniformly. 
In  the  case  of  calf,  goat,  and  sheep  skins,  fleshing 
machines  are  used  with  great  success ;  in  fact,  hand  flesh- 
ing has  been  displaced  almost  entirely  in  the  large  chrome 
tanneries,  as  machine  work  is  cheaper  and  more  regular 
in  output.  It  must  be  remembered,  however,  that  all  sole 
leather  is  invariably  sold  by  weight,  so  that  the  intelli- 
gence of  the  skilled  workman  is  very  useful,  as  much  un- 
necessary tissue  may  easily  be  cut  away  by  machine,  with 
the  result  that  the  slight  saving  in  labour  may  be 
swamped  in  the  deficient  weight  of  the  finished  leather. 

It  is,  however,  only  fair  to  add  that  there  are  several 
large  sole  leather  yards  turning  out  a  good  mixed  tan- 
nage of  sole  leather  which  now  use  the  fleshing  machine 
very  successfully,  so  that  it  is  probable  it  is  only  a 
question  of  time  when  the  old  beamsman  will  become  a 
thing  of  the  past.  Improvements  are  being  continually 
introduced,  and  the  prejudice  against  the  use  of  machinery 
passing  away,  whilst  the  unceasing  competition  of  the  times 
naturally  favours  the  application  of  any  piece  of  plant 
likely  to  cheapen  a  process  which  is  of  a  very  costly  nature. 
Machines  for  Crushing  and  Grinding  Tanning  Mate- 
rials.— As  this  chapter  does  not  profess  to  deal  with  the 
technique  of  tanning,  only  as  far  as  is  necessary  in 
explaining  the  use  of  machinery,  no  attempt  will  be 


MACHINERY  IN  LEATHER  MANUFACTURE.        405 

made  to  describe  the  tannins  in  detail.  Most  of  them, 
however,  require  some  preparation  by  machinery  in  the 
way  of  breaking  or  grinding  by  means  of  bark  mills  or 
disintegrators.  The  object  is  to  grind  the  material  so 
that  the  liquor  has  ready  access  to  the  interior  cellular 
tissue,  in  which  most  of  the  tannin  is  found.  The  bark 
mill  in  general  use  consists  of  a  toothed  cone  working 
inside  another  similarly  constructed  cone,  arranged  much 
on  the  same  principle  as  a  coffee  mill.  A  preparatory 
breaking  by  a  special  machine  is  also  necessary  where  the 
bark  to  be  ground  is  in  long  strips,  and  this  is  usually 
done  by  means  of  toothed  breakers.  A  common  form  of 
mill  is  constructed  by  the  well-known  Exeter  firm  of 
Huxham  and  Browns,  and  B.  and  D.  Wright,  Leeds.  An 
improved  bark  cutter  is  made  by  the  Turner  Machine 
Co.,  Peabody,  United  States,  and  is  durable,  simple, 
and  effective ;  and  it  is  claimed  by  the  inventors  that  it 
will  prepare  forty  cords  of  bark  per  day  for  the  leaches. 

Such  materials  as  valonia  and  myrobalans  are  usually 
broken  by  means  of  the  machines  known  as  disintegrators, 
such  as  are  used  to  pulverize  bones,  &c.  The  principle 
is  simple,  and  depends  upon  knocking  the  material  to 
powder  by  the  action  of  rapidly  revolving  beaters,  which 
in  some  cases  are  driven  at  a  speed  of  between  2,000  and 
3,000  revolutions  a  minute.  This  class  of  machinery  is 
very  effective,  but  the  consumption  of  power  is  rather 

freat,  whilst  the  fine  dust  is  apt  to  prove  troublesome, 
or  some  purposes  myrobalans  are  only  required  roughly 
crushed  by  the  tanner.  In  this  case  a  machine  with 
fluted  or  toothed  rollers  is  more  useful  than  a  disinte- 
grator, as  less  power  is  required  and  the  proportions  of 
dust  is  very  little.  Valonia — a  species  of  large  acorn  cup 
from  Southern  Europe — may  also  be  satisfactorily  crushed 
by  this  class  of  machinery.  The  most  common  form  of 
disintegrator  is  shown  in  Fig.  65. 

Many  other  varieties  of  devices  for  preparing  tanning 
materials  are  also  in  vogue,  but  the  examples  mentioned 
fairly  represent  the  general  principle  on  which  most  of 
them  are  constructed.  In  England  machinery  is  not 


406  LEATHER  MANUFACTURE. 

much  favoured  for  carrying  tanning  material  to  the 
leaches  or  extraction  pits,  but  in  America  "  conveyors  " 
of  various  kinds  are  freely  used.  These  consist  often 
of  endless  iron  chains  carrying  wooden  cross-bars  at 
intervals,  working  along  suitably  constructed  spouts. 
As  the  use  of  conveyors  is  only  profitable  in  large 
tanneries  where  labour  is  dear,  and,  furthermore,  their 


Fig.  65. 

design  has  already  been  explained  on  p.  161,  it  would 
serve  no  useful  purpose  to  here  further  enlarge  upon 
them. 

Sole  Leather  Finishing  Machinery. — Sole  butts  after 
tanning  are  usually  drained  of  surplus  liquor,  and  then 
are  given  a  coat  of  oil  on  the  grain  side  and  allowed  to 
partially  dry,  and  are  then  "  struck  "  or  "  pinned  "  out. 
The  object  is  to  stretch  and  render  the  grain  even,  and 
often  to  scour  out  as  much  bloom — a  whitish  deposit  left 
in  by  tanning — as  may  be  desirable  to  suit  the  require- 
ments of  the  market.  Many  tanners  of  best  quality  oak- 
bark  leather  still  persist  in  doing  this  by  hand,  using  a 


MACHINERY  IN  LEATHER  MANUFACTURE.        407 

triangular  tool  called  a  pin,  and  thoroughly  extending 
the  leather  over  a  horizontal  beam  or  "  horse." 

Of  late  years,  however,  machinery  has  been  successfully 
introduced  for  the  purpose,  and  nearly  all  the  biggest 
English  yards  employ  various  types  of  machines  for 
striking.  The  most  popular  form  of  machine  for  striking 
offal  is  that  invented  by  Priestinan  some  years  ago, 
the  principle  of  which  remains  the  same,  although  im- 
provements have  been  added  from  time  to  time.  A 
common  form  of  this  appliance  is  shown  in  Fig.  20, 
p.  165. 

The  principle  is  simple,  and  consists  of  a  revolving 
cylinder,  to  which  are  attached  V-shaped  blunt  brass 
knives,  under  which  the  leather  is  fed.  The  pressure  is 
regulated  by  a  foot-lever  acting  on  a  movable  bed.  The 
amount  of  work  turned  off  by  this  machine  is  very  great, 
but  it  is  not  very  well  adapted  for  irregular-shaped  pieces 
of  leather,  such  as  bellies,  &c. 

Many  tanners  now  use  the  striking  machine  for  butts 
invented  by  Wilson  (Fig.  66),  which  is  perhaps  as  near  an 
approach  to  hand  labour  as  can  be  obtained.  The  leather 
is  carried  over  a  revolving  drum,  and  the  grain  is  operated 
upon  by  blunt  knives  working  outwards  from  the  centre. 
Where  it  is  necessary  to  remove  the  bloom,  slabs  of  stock 
stone  are  substituted  for  the  knives.  This  piece  of  plant 
has  been  running  for  many  years  in  some  yards  and  has 
proved  a  valuable  help,  as  the  cost  of  striking  is  nothing 
like  so  great  as  hand  labour.  It  is,  however,  more  es- 
pecially useful  to  large  tanners,  as  the  first  cost  is  fairly 
high,  and  it  requires  a  firm  foundation,  the  oscillating 
motion  being  rather  pronounced.  A  modification  of  this 
type  of  machine  is  also  now  freely  used  for  pinning  offal. 

Sole  leather,  after  lightly  oiling  and  drying,  is  then 
submitted  to  a  rolling  operation  to  give  it  the  necessary 
solidity  and  firmness.  On  the  Continent  a  different 
method  prevails,  and  the  leather  is  well  hammered  by  a 
machine  known  as  the  Marteau-a-battre,  the  action  being 
much  the  same  as  that  of  the  well-known  steam 
hammer. 


MACHINERY  IN  LEATHER  MANUFACTURE.        409 

The  old  type  of  rolling  machine  consisted  simply  of  a 
loaded  box,  to  which  was  attached  a  brass  roller.  This 
was  dragged  over  the  butts,  which  were  spread  out  upon 
a  plank  or  zinc  bed,  and,  although  slow  and  cumbrous, 
the  method  is  still  regarded  as  the  perfection  of  leather 
rolling.  Fig.  22,  p.  166,  shows  a  form  of  spring  butt 
roller  by  Huxhain  and  Browns  in  which  the  necessary 
pressure  is  obtained  from  springs  placed  above  the  roller, 
which  runs  alternately  backward  and  forward  over  a  flat 
table  beneath  a  fixed  girder.  The  pendulum  roller, 
Fig.  23,  p.  167,  is  especially  suited  for  sides,  such  as  East 
India  kips  or  Singapore  leather,  in  which  great  firmness 
and  a  high  gloss  is  necessary.  The  roller  being  narrow 
lends  itself  readily  to  the  inequalities  of  substance,  and  its 
construction  is  very  convenient  to  the  manipulation  of 
the  irregular  belly  and  shank  portion  of  the  side  under 
treatment.  Its  oscillating  motion  causes  much  vibration 
and  noise,  so  that  it  is  best  fixed  wherever  possible  on 
the  ground  floor.  It  is,  however,  cheap,  easy  to  make 
and  repair,  and  well  adapted  to  special  classes  of  work  such 
as  are  mentioned  above. 

A  familiar  and  useful  type  of  machine  is  the  "  C " 
roller,  in  which  the  leather  is  passed  between  two  brass 
covered  rollers.  Practically  any  pressure  may  be 
obtained  by  a  weighted  lever  attached  to  the  top  roller, 
but  experience  has  shown  that  this  type  is  unsuitable  to 
butts,  as  it  destroys  the  flat  appearance,  or — to  use  a 
technical  expression — makes  them  "  baggy."  For  bellies, 
shoulders,  and  splits  this  variety  of  machine  is  very 
suitable,  as  the  cost  of  manipulation  is  not  great  by 
reason  of  the  quantity  of  work  done,  whilst  a  simple 
reversible  motion,  obtained  by  using  a  crossed  and  open 
belt,  obviates,  to  a  large  extent,  any  jumping  of  the 
rollers  when  narrow  pieces  of  leather  are  under  treatment. 
It  may  be  added  that  nearly  in  all  cases  leather  is  rolled 
twice,  the  two  operations  being  designated  "  rolling  on  " 
and  "  rolling  off."  After  complete  drying,  sole  leather 
is  ready  for  the  market,  although  in  some  cases  colouring 
composition  are  applied  to  the  grain  side,  and  a  final 


410  LEATHER  MANUFACTURE. 

brushing — which  is  now  often  done  with  a  machine — 
given  to  bring  up  an  attractive-looking  gloss. 

Leather  Dressing  Machinery. — Tne  mechanical  ap- 
pliances employed  under  this  heading  are  extremely 
numerous  and  ingenious,  and,  since  the  introduction  of 
the  chrome  tannage,  have  been  greatly  augmented, 
although  it  must  not  be  assumed  that  some  of  the 
machines  mentioned  here  are  not  both  used  on  chrome 
and  other  forms  of  leather  making. 

The  term  "  dressing  leather  "  is  fairly  comprehensive, 
and  embraces  harness,  saddlery,  mechanical,  accoutre- 
ment, boot  and  bookbinding  leathers,  &c.  Each  of  these 
branches  of  the  leather  industry  is  often  a  special  business, 
but  there  are  certain  types  of  machines  fairly  common  to 
all. 

As  most  tanned  leather  is  rough  and  uneven  when  it 
leaves  the  hands  of  the  tanner  for  the  currier,  it  is  there- 
fore necessary  to  equalize  the  substance  in  some  measure. 
For  harness  and  belting  leather  it  is  only  usual  to  remove 
the  loose  flesh  and  the  marked  inequalities  of  the  butt, 
but  for  such  purposes  as  shoe  leather,  which  depend  upon 
a  flesh  side  finish,  this  preliminary  operation  is  very  com- 
plete, and  is  technically  known  as  shaving,  an  operation 
requiring  a  long  training  and  a  high  pitch  of  perfection. 
Within  recent  years  this  process,  which  is  done  by 
laboriously  paring  the  hide  or  skin  with  a  suitable  knife 
over  an  inclined  "  beam "  or  block  of  lignum  mtce 
(Fig.  58,  p.  371),  has  been  successfully  attempted  by 
machine  (Fig.  67) ;  in  fact,  by  far  the  greater  part  of 
chrome  tanned  leather  is  now  shaved  in  this  way. 
Chrome  leather,  mainly  on  account  of  the  looseness  of 
its  texture,  is  difficult  to  shave  by  hand,  whilst  the 
cost  on  goat  skins  makes  it  almost  prohibitive.  The 
principle  of  the  shaving  machine  depends  upon  passing 
the  damp  leather  under  a  rapidly  revolving  cylinder, 
to  which  is  attached  a  series  of  steel  knives,  kept  auto- 
matically sharpened  by  emery  wheels.  The  leather 
is  pushed  up  to  the  knives  by  a  foot-lever  actuating  a 
rubber  roller,  and  by  a  screw  arrangement  the  distance 


MACHINERY  IN  LEATHER  MANUFACTURE.        411 

between  the  cutting  and  cushion  cylinders  may  be 
regulated  to  suit  the  requirements  of  the  operator.  This 
piece  of  currier's  plant  is  one  of  the  most  ingenious  yet 
introduced,  and  is  fast  superseding  hand  labour  on  the 
lightest  classes  of  goods.  It  is,  however,  yet  capable  of 
improvement,  as  it  is  rather  dangerous  to  the  operator, 
and  somewhat  deficient  in  reducing  power  on  a  close, 
firm  texture,  whilst  the  flying  emery  and  steel  dust  is  apt 
to  stain  ordinary  vegetable  tanned  leather. 


Fig.  67. 

In  practice  both  untanned  and  tanned  hides  are  often 
divided  into  two  or  more  portions  by  machine.  The 
principle  employed  in  splitting  "  green  "  hides  and  skins 
consists  in  passing  the  swollen  and  limey  pelt  over  a 
wooden  drum,  whilst  the  division  is  made  by  the  action 
of  a  rapidly  vibrating  knife.  Attempts  have  been  made 
to  do  green  splitting  by  means  of  the  band-knife  machine 
(see  Fig.  68),  with  a  fair  measure  of  success,  and  there 
seems  no  real  reason  why  the  difficulties  should  not  be 
conquered  with  a  little  determined  ingenuity. 


412 


LEATHER  MANUFACTURE. 


Tanned  leather  is  now  almost  universally  split  on  the 
band-knife  machine  before  mentioned.  As  the  name 
implies,  the  cutting  is  done  by  means  of  an  endless  steel 
belt,  which  travels  over  two  large  pulleys,  the  edge  being 
kept  sharp  by  the  automatic  grinding  of  emery  wheels 
below  the  machine.  The  machine  is  rather  complicated 
and  fairly  expensive,  but  remarkably  useful.  The  damp 
leather  is  fed  between  brass  rollers  to  the  knife's  edge, 
the  inequalities  being  provided  for  in  the  under  roller  by 


small  eccentric  brass  sections,  which  in  turn  press  upon  a 
resilient  rubber  cylinder.  This  machine  is  capable  of 
getting  through  an  enormous  quantity  of  work,  but 
requires  the  services  of  a  skilled  and  intelligent  operator 
to  secure  good  results.  Butts  for  army  upper  and 
kindred  purposes  are  split  on  an  older  form  of  machine 
known  as  the  "Union"  (Fig.  54,  p.  322),  the  leather 
being  pressed  down  and  drawn  over  a  fixed  knife.  For 
work  of  this  class  this  machine  has  some  advantages,  as 
the  split  leather  is  more  even  in  substance. 


MACHINERY  IN  LEATHER  MANUFACTURE.        413 

Scouring  and  Setting  Machinery. — During  the  pro- 
cess of  tanning  by  immersion  in  bark  liquors,  &c.,  the 
grain  side  of  the  leather,  as  already  stated,  becomes  more 
or  less  filled  with  a  whitish  deposit  called  "  bloom," 
known  to  chemists  as  ellagic  acid.  In  most  cases  it  is 
necessary  to  remove  this,  as  it  interferes  with  subsequent 
operations.  The  principle  of  the  scouring  machines  is 
much  the  same  as  that  followed  out  in  sole-leather 
"  pinning,"  where,  indeed,  the  object  aimed  at  is  almost 
identical.  As  a  matter  of  fact,  it  is  usually  only  the 
heavier  classes  of  upper  belting  and  harness  leather 


Fig.  69. 

which  are  scoured  by  mechanical  aid,  and  for  this  purpose 
a  machine  of  the  type  illustrated  in  Fig.  69  is  used  to  some 
extent  in  England.  The  leather  is  spread  in  a  wet  con- 
dition on  a  movable  table,  and  is  subjected  to  the  action 
of  a  reciprocating  head,  which  has  a  most  ingenious 
motion.  The  amount  of  work  these  appliances  get 
through  is  very  great ;  but  the  first  cost  is  heavy,  and, 
in  consequence,  they  have  to  be  fairly  fully  employed  to 
be  profitable. 

An  older  type  of  machine,  known  as  the  "Bourdon 
Scourer,"  is  shown  at  Fig.  17,  p.  156.    In  this  case  the 


4*4  LEATHER  MANUFACTURE. 

wet  leather  is  passed  under  a  cylinder  into  which  are 
fixed  projecting  slabs  of  stone,  which  revolve  at  a  high 
rate  of  speed,  the  leather  of  course  being  pressed  up  to 
the  revolving  working  part  by  means  of  foot-levers 
actuating  a  suitable  cushion.  This  machine  is  suitable 
for  heavy  leathers  for  military  purposes,  &c.,  but  is  little 
used  for  the  finer  classes  of  manufacture. 

Leather  is,  after  drum-stuffing,  extended  or  "  set "  to 
eliminate  the  stretch  and  to  give  it  pattern,  and  then 
dried.  The  same  operation  is  necessary  for  chrome 
tanned  leather  after  milling  in  fat-liquor,  which  is 
simply  a  weak  emulsion  of  soap  and  oil  modified  to 
suit  the  particular  method  of  leather  manufacture.  As 
the  labour  involved  in  setting  is  rather  excessive,  but 
purely  mechanical,  machinery  has  been  introduced  with 
great  success  in  recent  years.  For  belting  leather  the 
type  shown  at  Fig.  69  is  also  used  for  this  purpose,  but 
there  is  no  standard  machine  used  by  upper-leather 
manufacturers  for  setting,  although  many  machines  are 
capable  of  doing  good  work  at  a  low  cost  where  the  shape 
of  the  leather  is  fairly  regular. 

Embossing  and  Softening  Machines — Certain  leathers 
for  shoe,  upholstery,  bag,  and  fancy  purposes  are  often 
printed  or  embossed  to  imitate  the  natural  marking  of 
some  other  skin ;  thus  sheep  skin  or  basil  is  frequently 
stamped  with  a  design  to  imitate  morocco  or  alligator 
hide,  whilst  cow-hide,  and  even  the  flesh  split,  is 
embossed  and  finished  to  imitate  the  well-known  marking 
of  pigskin  for  legging  purposes.  Levant  and  memel 
leather  for  common  and  heavy  boots  are  embossed  with 
popular  patterns,  termed  "star,"  "pebble,"  &c.,  and 
thousands  of  Bombay -tanned  kips  are  stamped  with 
a  long  barley-shaped  grain  and  sold  as  cow-hide.  All 
the  smaller  skins  are  embossed  by  passing  them  in  a 
damp  condition  beneath  an  engraved  roller.  The  more 
simple  designs  are  cut  by  hand  on  iron  or  copper  rolls, 
the  more  elaborate  being  electrotyped,  whilst  floral  and 
artistic  designs  are  impressed  by  submitting  the  leather 
to  pressure  under  a  prepared  plate.  The  ordinary  form 


MACHINERY  IN  LEATHER  MANUFACTURE.         415 

of  embossing  machine  is  shown  at  Fig.  81,  p.  432.  The 
embossing  roller  is  now  made  in  the  shape  of  a  hollow 
cylinder,  and  is  thus  easily  removed  from  the  working 
spindle.  The  most  common  size  in  use  is  the  4  it.  6  in. 
machine,  which  takes  the  kip  side  or  sheep  skin  quite 
easily.  The  smaller  machines  with  5-in.  or  6-in.  rollers 
are  now  seldom  used,  as  the  larger  machine  turns  out 
the  work  faster  and  better. 

Tanning  and  Stuffing  Drums  or  Tumblers. — As  drum- 
tumblers  are  used  by  the  tanner  and  light  leather  manu- 
facturer very  freely,  it  will  be  perhaps  necessary  to  say 
a  few  words  on  them  here,  although  these  machines  have 
been  to  some  extent  dealt  with  in  the  chapter  on  Kip- 
Leather  Currying.  The  form  of  tumbler  illustrated  in 
Fig.  70,  p.  416,  gives  a  fair  idea  of  its  construction  and 
form ;  but  it  will  be  seen  from  the  design  which  appears 
here  that  the  drum  is  capable  of  many  modifications. 
Some  users  prefer  the  door  in  the  side  as  shown  in  Fig. 
70,  whilst  others  insist  upon  having  the  opening  in 
the  centre,  The  latter  style  has  the  advantage  that 
the  drum  may  be  swung  upon  an  axle,  and  this  is  a 
decided  help  when  power  and  vibration  are  considerations. 
Some  makes  of  tumblers  are  fitted  with  pegs  standing 
up  in  the  interior ;  others,  again,  possess  shelves.  A 
good  deal  depends  upon  the  class  of  work  required,  or 
the  individual  fancy;  but  as  the  experience  of  expert 
engineers  is  always  available,  it  is  not  necessary  to  take 
up  valuable  space  by  going  very  fully  into  these  points. 
It  is  important,  however,  to  note  that  a  tanner's  tumbler 
should  be  strongly  built  of  the  best  seasoned  timber,  and 
that  all  exposed  iron  work  is  covered  with  some  material 
which  does  not  corrode  by  the  action  of  the  tannic  acid  ; 
otherwise  stained  and  spoilt  leather  is  a  certain  result. 
These  drums  are  also  used  for  tanning  proper,  bateing, 
washing,  &c.,  by  the  upper  leather  tanner,  whilst  the 
manufacturer  of  the  lighter  leathers  finds  them  indis- 
pensable for  re-tanning,  sumacing,  dyeing,  stuffing, 
and  a  host  of  other  purposes  which  will  readily  occur 
to  the  reader.  In  chrome  tanning,  too,  the  drum  is 


4i6 


LEATHER  MANUFACTURE. 


wanted  in  many  ways,  so  that  simple  though  this  piece 
of  tanning  plant  may  be,  yet  it  is  important  enough 
to  warrant  the  attention  of  the  leather  trades'  engineer, 
who  has  succeeded  in  improving  it  in  many  ways  during 
the  past  few  years.  The  improved  form  of  stuffing-drum 
shown  in  Fig.  70  is  fitted  with  an  apparatus  for  intro- 
ducing the  melted  greases  and  hot  air. 


Fig.  70. 

"Boarding"  and  Softening  Machines. — Many  forms 
of  leather  have  to  be  softened  by  mechanical  means,  and 
various  methods  are  employed  to  do  this,  according  to  the 
characteristics  required.  The  old-fashioned  tool,  which 
is  still  used  to  a  large  extent,  consisted  of  a  suitably 
covered  pommel,  which  was  attached  to  the  hand  or  arm 
under  which  the  leather  was  rubbed.  This  has  the  dual 
effect  of  softening  the  leather  and  bringing  up  the 


MACHINERY  IN  LEATHER  MANUFACTURE.        417 

familiar  pattern  of  the  marking  of  the  grain.  Tho 
softening  of  levant  shoe  leathers  is  now  done  extensively 
by  machinery,  and  for  the  rougher  part  of  the  work  it 
has  completely  displaced  the  hand  process.  A  common 
type  of  softening  machine  is  shown  at  Fig.  71.  In 
mineral  tannages,  such  as  alum  and  salt,  or  chrome,  the 
softening  or  stretching  of  the  fibre  is  an  expensive 
business,  and  special  machines,  described  in  the  section 
dealing  with  Chrome  Leather  Machinery,  are  freely  used. 
The  final  operation  necessary  to  the  finishing  of  most 
upper  leathers  which  are  dressed  with  grease,  and  which 


Fig.  71. 


is  termed  whitening,  is  now  often  done  by  machine. 
The  operation,  including  that  of  "  buffing "  the  grain 
side,  is  done  to  some  extent  by  an  ingenious  revolving 
cylinder  of  knives,  which  is  given  a  sort  of  reciprocating 
motion.  Attempts  to  use  it  have  only  been  partially 
successful  in  England,  mainly  because  the  shoe  manu- 
facturer demands  a  very  fine  "  face,"  or  density  of  fibre, 
which  is  not  easily  obtained  by  machine,  so  that  in  some 
cases  this  final  operation  is  carried  out  by  cutting  the 
surface  of  the  leather  by  sharp  turned  edges  of  a  tem- 
pered steel  plate  on  an  absolutely  level  surface.  The 

2  E 


4i8 


LEATHER  MANUFACTURE. 


whitening  machine  in  use  in  America,  and  to  a  limited 
extent  in  England,  is  shown  in  Fig.  72. 


Fig.  72. 

Minor   operations   in    leather   manufacture,  such    as 
blacking,  glassing,  brushing,  fluffing,  &c.,  are,  of  course, 


MACHINERY  IN  LEATHER  MANUFACTURE.        419 

often  executed  by  machinery ;  but  the  design  of  these 
mechanical  aids  is  simple,  and  their  use  so  well  under- 
stood that  no  space  need  be  taken  up  with  their 
description. 


MACHINERY  USED  IN  CHROME  LEATHER  MANUFACTURE. 

The  rapid  development  of  this  branch  of  leather  manu- 
facture by  America  has  given  an  impetus  to  the  use  of 
machinery  that  was  little  anticipated.  The  necessity  for 
keeping  the  work  going  in  an  unbroken  stream  has 
doubtless  had  much  to  do  with  this,  whilst  declining 
profits  and  the  high  rate  of  wages  paid  for  certain  opera- 
tions have  all  favoured  the  engineer.  The  enormous 
quantities  of  skins  turned  out  by  some  of  the  great 
Philadelphia  houses  are  almost  beyond  belief,  as  several 
calculate  their  output  at  from  two  to  three  thousand 
dozen  glazed  goat  skins  per  day.  It  will  be  seen,  there- 
fore, that  the  difficulty  of  finding  and  controlling  labour 
for  such  a  trade  is  very  great,  and  that  the  business  has 
been  built  up  largely  by  the  co-operation  of  the  engineer 
with  the  practical  tanner. 

machinery  used  in  the  Beam  House. — It  is  now 
possible  to  do  almost  every  operation  in  what  is  known 
as  the  "  wet  work  "  by  machine,  and  a  brief  summary  of 
the  machines  usually  employed  may  be  useful  as  showing 
how  independent  the  large  American  or  European  tanner 
is  of  skilled  labour.  Taking  Patna  dried  goat  skins  as 
an  example :  these  are  usually  well  soaked  in  plenty  of 
clean  water,  to  which  a  little  borax  may  be  added  with 
advantage,  and  are  often  mechanically  softened  by 
"  stocking  "  or  drumming  for  twenty  minutes  or  so.  In 
small  yards  the  work  is  done  by  hand  by  "  breaking  " 
over  the  tanner's  beam  with  a  blunt  knife. 

The  next  step  is  to  plump  the  skins  and  loosen  the 
hair,  which  is  done  by  immersing  them  in  a  solution  of 
lime  and  arsenic  sulphide.  Unhairing  is  a  cheap  opera- 
tion, but  takes  room,  so  that  the  use  of  machines  has 


420 


LEATHER  MANUFACTURE. 


been  introduced  with  success,  and  as  the  same  type  of 
machine  is  used  later  on  in  the  manufacture  of  chrome 
leather,  the  illustration  at  Fig.  73  may  be  studied  with 
advantage.  The  skins  are  simply  spread  in  a  folded 
condition  on  each  side  of  the  vertical  table,  which  by  an 
ingenious  motion  passes  between  two  revolving  rollers, 


Fig.  73. 


both  of  which  are  fitted  with  blunt  knives,  and  revolve 
in  different  directions.  The  dehairing  is  not  done  very 
clean,  but  what  remains  is  easily  disposed  of  in  a  subse- 
quent process.  Other  types  of  machines  are  also  favoured 
for  unhairing,  and  an  enormous  amount  of  work  can  be 
done  on  a  modified  form  of  the  machine  shown  for  sole 
leather  at  Fig.  64  (p.  403),  whilst  there  are  others  equally 


MACHINERY  IN  LEATHER  MANUFACTURE. 


421 


good  upon  the  market — such  as  that  shown  at  Fig.  74. 
The  one  drawback  to  the  use  of  machines  for  this  purpose 
is  the  rather  large  proportion  of  damage  done  to  imperfect 
stock. 

After  unhairing  the  goat  skins  are  usually  fleshed. 
This  process,  being  a  skilled  and  expensive  one,  is  now 
generally  executed  by  a  machine,  the  principle  of  which 


Fig.  74. 

is  much  the  same  as  that  shown  in  Fig.  64  (p.  403)  or 
Fig.  74,  made  by  the  Turner  Co.,  Peabody,  U.S.A.  The 
limey  and  swollen  skins  are  spread  on  a  rubber-covered 
roller,  and  are  passed  under  a  cylinder  fitted  with  knives, 
which  are  so  arranged  as  to  spread  the  skin  outwards 
from  the  centre.  It  is  as  well  to  remember  that  very 
imperfect  skins  are  best  done  by  hand,  as  the  rapid 
action  of  the  machine  makes  it  impossible  to  guard 
against  further  damage. 


422  LEATHER  MANUFACTURE. 

Passing  on  to  deliming,  or  "puring,"  as  it  is  techni- 
cally called,  it  is  useful  to  note  that,  even  here,  mechanical 
aid  is  necessary.  Instead  of  the  old-fashioned  plan  of 
immersing  the  skins  in  tubs  containing  the  puring 
solutions,  they  are  now  almost  always  kept  on  the  move 
by  agitation  in  paddle  tanks.  The  time  of  this  very 
disagreeable  operation  is  thereby  considerably  shortened, 
and  the  danger  of  damage  to  the  goods  reduced  to  a 
minimum.  After  the  pure  has  "  brought  the  skins  down," 
i.e.  reduced  the  plumpness  caused  by  the  lime,  &c.,  a 
further  working  called  "  scudding  "  is  necessary  to  expel 
the  short  hair,  hair  cells,  pigment,  and  lime,  soap,  fat, 
&c.,  otherwise  the  resultant  leather  would  be  an  inferior 
quality. 

This  operation  is,  in  most  progressive  yards,  now  done 
by  machine,  the  skin  passing  over  a  rubber-covered 
cylinder,  whilst  slate  tools  projecting  from  an  upper 
cylinder  more  or  less  thoroughly  cleanse  the  grain  from 
impurities  which,  if  not  removed,  would  seriously  inter- 
fere with  the  beautiful  glazed  appearance  of  the  finished 
leather.  As  scudding  is  also  done  on  much  the  same 
class  of  machine  as  that  for  fleshing — in  fact,  the  same 
machine  is  often  used  with  the  insertion  of  a  special 
roller — it  is  not  necessary  to  illustrate  this  appliance. 
Gloat  skins  for  chrome  leather  are  after  scudding  thoroughly 
washed  in  plenty  of  water  and  passed  on  to  the  actual 
tanning  operation.  As  already  explained,  this  consists  of 
immersing  the  pelts  in  a  solution  of  bichromate  of  potash 
and  hydrochloric  acid  for  a  few  hours,  and  then  trans- 
ferring them  to  a  reducing  bath  of  hyposulphite  of  soda 
and  hydrochloric  acid.  This  is  followed  up  by  a  washing 
in  borax  or  some  other  alkali  to  neutralise  the  acid 
present.  The  actual  tanning  is  carried  out  in  the  paddle 
vat  or  tumbler — generally  the  former — already  described, 
and  the  skins  after  the  bichromate  bath  are  struck  out 
by  a  machine  of  the  type  shown  in  Fig.  73.  The  subse- 
quent processes  of  "  fat-liquoring  "  and  dyeing  are 
ordinary  operations,  and  require  no  special  comment  in 
a  section  which  only  professes  to  touch  on  the  technique 


MACHINERY  IN  LEATHER  MANUFACTURE.        423 

of  the  chrome  process,  as  far  as  it  is  necessary  to  elucidate 
the  working  of  mechanical  appliances.  The  striking-out 
operation  referred  to  above  is  repeated  several  times  as 
required,  the  final  "  setting "  or  permanent  extension 
being  also  given  on  the  same  machine.  The  operation 
is  quite  simple,  the  skin  being  folded  down  the  back 
upon  a  vertical  table  which  rises  between  two  spiral 
knife-covered  rotating  cylinders.  The  effect  is  to 
thoroughly  stretch  the  skin  and  to  make  the  desirable 
line  grain.  It  is  easy  to  use,  one  man  and  a  boy  being 
ample  to  attend  to  it,  whilst  the  quantity  of  work  got 
through  is  very  great.  Chrome  leather  shaving  is  now 
carried  out  on  the  machine  shown  in  Fig.  67  (p.  411) ; 
results  have  proved  that  chrome  leather  is  absolutely  un- 
fitted to  hand  labour,  as  the  leather  is  exceedingly  difficult 
to  cut  in  any  stage,  and  especially  so  in  the  "  blue " 
condition,  i.e.  after  the  reducing  bath.  The  lighter  kinds 
of  goat  skins  cost  very  little  indeed  to  shave  by  machine, 
as  they  are  fairly  level,  and  only  need  reducing  towards 
the  head  of  the  skin,  whilst  plenty  require  no  more  than 
a  slight  stroke  to  level  them  sufficiently  to  meet  the 
market  requirements. 

Finishing  Machinery  for  Chrome  Werk. — Most  of 
the  operations  in  the  "  dry  work "  are,  in  all  the  large 
manufactories,  now  executed  by  machine,  as  the  cost  is 
not  to  be  compared  with  hand  labour.  The  appliances 
used  are  mainly  for  softening  and  polishing,  and  as  each 
skin  has  to  undergo  these  operations  several  times,  the 
cost  even  with  machinery  is  fairly  great.  The  dyed 
goat  skin  is,  as  we  have  already  shown,  after  fat- 
liquoring,  dyed,  "struck,"  and  set  out,  given  a  coat 
of  glycerine  and  neatsfoot  oil  and  dried  at  a  high 
temperature.  The  leather  at  this  stage  is  hard  and 
"  tinny,"  and  requires  plenty  of  mechanical  work  to 
bring  it  to  a  saleable  condition.  After  cooling  down 
and  storing,  the  skins  are  usually  damped  back  by 
placing  them  in  damp  sawdust  for  a  few  hours,  and  are 
then  staked  or  softened  by  machinery.  In  the  early 
days  of  chrome  leather  manufacture,  this  process  was 


MACHINERY  IN  LEATHER  MANUFACTURE. 


425 


done  by  drawing  the  damp  skin  over  a  steel  plate  fixed 
into  a  wooden  post,  the  knee  being  the  main  source  of 
power,  whilst  the  hands  were  used  to  guide  and  mani- 
pulate the  skin.  Another  plan  was  to  attach  the  skin 
to  an  upright  "  perch,"  and,  by  means  of  a  short  crutch, 
which  had  a  steel  plate  at  its  extremity,  the  leather  was 
extended  in  every  direction.  These  crude  methods  are 
now  gradually  becoming  obsolete,  and  the  machine  shown 


Fig.  76. 

in  Fig.  75  is  one  of  the  best  tools  for  the  purpose.  The 
action  is  very  simple,  the  leather  being  pulled  between 
two  steel  plates;  the  opening  and  closing  motions  of 
the  jaws  of  the  machine  are  quite  novelties  in  leather 
appliances,  and  are,  in  fact,  somewhat  startling  to  a 
beginner.  As  the  operator  has  to  take  the  entire  "  pull " 
of  the  machine  by  the  pressure  of  his  body  to  the  leather, 
it  is  well  to  put  a  fairly  strong  man  to  work  it,  otherwise 
accidents  might  occur,  or,  at  least,  imperfect  skins  get 


or  THE 


426 


LEATHER  MANUFACTURE. 


hopelessly  damaged.  There  are,  of  course,  other  staking 
machines  on  the  market,  but  the  principle  is  much  the 
same.  The  skins  are  staked  twice,  or  even  three  times, 
according  to  requirements,  and  are  usually  glazed  after 
each  staking.  The  foundation  for  the  glaze,  consisting 
of  a  weak  solution  of  blood  albumen,  is  usually  applied 
with  a  soft  pad  to  the  grain  side  of  the  skin,  and  partially 
or  wholly  dried  before  passing  on  to  the  machine.  The 


Fig,  77. 

flesh  side,  too,  is  often  "  fluffed,"  i.e.  abraded  on  a  wheel, 
much  on  the  principle  of  the  grindstone,  with  the 
difference  that  fairly  coarse  emery  powder  is  the  abrasive 
medium.  The  wheel  is  of  iron,  and  is  shod  with  a  stout 
wooden  tyre  slightly  rounded  off,  this  forming  the  bed 
for  the  emery.  The  dust  from  the  operation  is  very 
troublesome,  but  is  removed  to  a  large  extent  by  well- 
arranged  fans,  which  draw  it  away  from  the  operator  to 


MACHINERY  IN  LEATHER  MANUFACTURE. 


427 


a  suitably  placed  receptacle.     A  familiar  type  of  this 
machine  is  shown  at  Fig.  76. 

The  final  operation  of  glazing  is  certainly  one  of  the 
most  important  in  the  manufacture  of  chrome  kid,  and 
involves  a  great  amount  of  technical  skill.  The  staking 


Fig.  78. 

has  had  the  effect  of  disturbing  the  "  lay  "  or  pattern  of 
the  skin,  and  unless  the  manipulation  is  almost  perfect, 
the  damage  done  by  the  rapid  action  of  the  polishing 
tool  is  apt  to  be  very  great.  Types  of  machines  used  are 


428 


LEATHER  MANUFACTURE. 


shown  at  Figs.  77  and  78.  These  are  more  generally  used 
for  glazing  vegetable  tanned  leather,  whilst  Fig.  79  has 
some  special  points  of  excellence,  which  make  it  specially 
suitable  for  polishing  light  chrome  stock.  For  goat, 
however,  a  spring  head  is  used.  The  frames  may  be 
either  of  wood  or  iron,  but  the  former  is  claimed  to  give 
a  greater  resiliency,  which  has  a  beneficial  effect  on  light 


Fig.  79. 

and  thin  stock.  Keference  to  the  illustrations  will 
show  that  the  working  arm  carries  a  small  cylinder  of 
glass  or  agate,  which  strikes  the  extended  skin  with  a 
rapid  downward  motion.  The  rate  of  speed  varies, 
according  to  the  work  and  the  fancy  of  the  operator, 
from  80  to  120  strokes  per  minute.  The  oscillating 
motion  caused  by  this  class  of  machine  is  great,  and 


MACHINERY  IN  LEATHER  MANUFACTURE. 


429 


it  should  be  very  firmly  fixed,  both  from  above  and 
below,  if  good  results  are  to  be  obtained,  otherwise 
the  damage  from  broken  skins  and  glazing  glasses 
is  apt  to  prove  rather  an  expensive  item.  Probably 
users  of  this  machine  would,  under  any  circumstances, 
do  well  to  remember  that  it  is  a  costly  business  to 


Fig.  80. 

train  operatives  for  this  process,  so  that  only  the  most 
intelligent  men  should  be  selected. 

Before  concluding  this  article  on  the  mechanical 
appliances  used  in  chrome  leather  manufacture,  it  may 
be  mentioned  that  a  measuring  machine  has  now  become 
an  indispensable  adjunct  to  a  works  of  any  size  (Fig.  80)  ; 
this  is  in  America  and  Europe  the  recognised  standard 
for  leather-measuring  between  buyer  and  seller.  The 
skin,  in  travelling  through  the  machine,  affects  the 
measuring  segments  arranged  close  together,  which  in 
turn  are  registered  on  an  index,  carefully  noted  by  the 
operator,  and  marked  on  the  skin.  This  machine  is  very 
ingenious,  and  soon  pays  for  the  cost  of  the  outlay  as 
every  inch  of  the  leather  is  calculated;  and  as  all 


430  LEATHER  MANUFACTURE. 

chrome  leathers  are  sold  by  surface  measurement,  it  will 
be  seen  that  it  is  an  absolute  necessity  that  this  end  of 
the  business  should  be  well  looked  after. 

The  most  recent  idea  for  measuring  the  superficial  area 
of  leather  is,  however,  Connolly's  Areameter.  The  instru- 
ment is  simplicity  itself,  and  broadly  consists  of  a  set  of 
geared  wheels,  to  which  are  attached  a  convenient  arm 
carrying  a  pointer.  This  latter  is  passed  around  the  edge 
of  the  skin  to  be  measured,  and  the  result  read  off  on  a 
dial  attached  to  the  central  part  of  the  machine.  After 
exhaustive  tests,  made  by  Dr.  Glazebrook  of  the  National 
and  Physical  Laboratory,  the  Areameter  has  been  recog- 
nised as  an  official  standard  by  the  Board  of  Trade  ;  and 
at  a  recent  meeting  of  the  Leather  Trade  Section  of  the 
London  Chamber  of  Commerce  it  was  recommended  to 
the  trade  "  for  verifying  the  measurement  of  leather  and 
skins,  and  as  a  means  of  determining  disputes  between 
buyer  and  seller."  The  machine  is  put  on  the  market 
by  Connolly's  Areameter  Company,  Brighton  Chambers, 
Denman  Street,  London  Bridge,  London,  S.E.,  and  is 
made  in  various  sizes  to  suit  the  convenience  of  users. 

In  bringing  this  article  to  a  close,  it  may  be  said  that 
no  attempt  has  been  made  to  go  fully  into  the  technical 
details  of  leather  manufacture ;  the  idea  has  been  simply 
to  give  just  a  few  practical  hints  to  readers  who  may 
not  be  familiar  with  the  class  of  machines  mentioned. 
Further  particulars  relating  to  the  chrome  process  have 
already  been  given  in  another  chapter. 


CHAPTER  XXXIT. 
EMBOSSING  LEATHER. 

Copying  Crocodile,  Alligator,  &c.,  Skins. 

THE  art  of  embossing  and  otherwise  ornamenting  leather 
dates  back  from  a  very  early  period,  the  Egyptians 
having  practised  the  art  nearly  three  thousand  years  ago. 
At  a  much  later  date,  namely,  about  the  thirteenth  cen- 
tury, the  art  appears  to  have  been  extensively  practised 
not  only  in  Italy  and  Spain,  but  also  in  England,  many 
specimens  of  which  are  still  extant. 

The  more  modern  applications  of  embossed  leather  have 
been  chiefly  devoted  to  leather  employed  in  bookbinding, 
furniture,  bags  and  reticules,  purses,  and  other  fancy 
articles ;  while  still  more  recently — with  the  aid  of  the 
electrotype  process — moulds  of  reptile  skins,  as  those  of 
the  crocodile,  alligator,  &c.,  have  been  taken,  by  means  of 
which  excellent  imitations  of  the  natural  skins  have  been 
produced,  possessing  all  the  beauty  of  the  original  skins 
at  a  lower  cost  to  the  purchaser. 

Embossing  machines  are  made  by  the  following  firms 
of  engineers :  Messrs.  Joseph  Hall  &  Co.,  T.  Haley  &  Co., 
B.  and  D.  Wright,  Leeds,  and  Messrs.  Farrar  &  Young, 
Bramley.  The  Moenus  Machine  Co.,  Frankfort-on-Main, 
also  make  embossing  machines,  their  latest  design,  "  The 
Altura,"  being  one  of  the  most  successful  pieces  of  plant 
ever  put  on  the  market  for  leather  work.  Messrs.  Huxham 
&  Brown,  of  Exeter,  have  also  lately  introduced  a  special 
kind  of  machine  for  the  purpose,  and  the  writer  has  seen 
excellent  work  done  by  it  in  a  very  rapid  and  effective 
manner. 


432  LEATHER  MANUFACTURE. 

Copying  Crocodile,  Alligator,  &c.,  Skins  by  Electro- 
type— It  will  be  readily  understood  that  by  the  electro- 
type process  perfect  impressions  of  the  skins  of  the 
crocodile,  alligator,  boa  -  constrictor,  and  other  reptile 
skins  can  be  obtained,  and  from  the  copper  moulds  thus 


Fig.  81. 

produced,  leather,  previously  damped  with  water,  can  be 
impressed,  and  exact  copies  of  the  original  obtained  to  an 
unlimited  extent.  By  the  same  process  morocco,  seal,  and 
other  skins  are  reproduced,  and  form  an  extensive  and 
greatly  increasing  branch  of  leather  manufacture,  some  of 


Fig.  82. 


the  results  obtained  being  exceedingly  beautiful,  the  finest 
markings  of  the  grain  being  reproduced  with  perfect 
fidelity.  Electrotyped  copper  rollers  and  plates,  bearing 
the  pattern  of  real  skins,  can  now  be  obtained  for  the 
manufacture  of  almost  any  variety  of  imitation  leather, 
and  from  each  roller  several  thousand  copies  may  be 


EMBOSSING  LEATHER. 


433 


produced.  In  Fig.  81  is  shown  the  ordinary  form  of 
embossing  and  printing  machine  made  by  the  above- 
named  firms,  and  in  Fig.  82  is  represented  an  electrotyped 
copper  roller.  Small  hand-presses  are  made  by  the  same 


Fig,  83. 

firms  for  printing  from  electrotype  plates  of  real  skins  up 
to  22  inches  by  27  inches,  the  embossing  machine  being 
employed  for  larger  surfaces.  An  illustration  of  one  of 
these  hand  machines  is  shown  in  Fi£.  83. 


CHAPTER  XXXIII. 
FELLMONGERING. 

Classification  of  Sheep  Skins.  —  Treatment  of  the  Sldns. 


ff,  or  removing  the  wool  from  sheep 
and  lamb  skins,  is  a  distinct  and  separate  trade,  more 
especially  in  London,  the  art  is  sometimes  combined  with 
the  other  operations  of  the  light  leather  manufacturer  in 
some  parts  of  the  country,  and  therefore  a  brief  descrip- 
tion of  the  method  of  treating  sheep  skins  by  the  fell- 
monger  will,  it  is  hoped,  be  useful.  Indeed,  even  if  not 
practised  by  the  skinner  or  manufacturer  of  light  leather, 
he  should  at  all  events  be  conversant  'with  the  method 
adopted  to  free  the  skins  from  wool  before  they  come  into 
his  hands,  since  this  will  enable  him  to  judge  from  the 
appearance  of  the  pelts  whether  the  process  has  been  pro- 
perly conducted  or  clumsily  and  carelessly  performed  ;  and 
it  is  well  known  that  fellmongered  skins  have  frequently 
exhibited  unmistakable  signs  of  careless  and  injudicious 
treatment.  Sometimes  the  skins  have  been  piled  in  heaps 
to  make  them  sweat,  producing  incipient  putrefaction,  by 
which  the  workman's  labour  in  removing  the  wool  was 
rendered  easier  ;  but  the  effect  of  this  is  that  much  of  the 
substance  of  the  skin  is  rendered  soluble,  even  in  cold 
water,  and  consequently  the  skins  suffer  loss  in  weight 
when  passed  through  weak  lime  liquors. 

The  London  fellmongers,  who  conduct  their  business 
upon  a  very  extensive  scale,  and  with  every  possible  eare, 
have  a  high  reputation  for  the  excellence  of  their  sheep 
pelts;  the  same  may  be  said  of  many  of  the  provincial 


FELLMONGERING.  435 

fcllmongers,  who  know  the  importance  of  having  their 
workmen  well  supervised  when  conducting  operations  re- 
quiring skill  and  judgment. 

Classification  of  Sheep  Skins. — The  skins  of  sheep 
slaughtered  in  Great  Britain  are  divided  into  large,  medium, 
and  small  skins,  and  may  be  arranged  under  the  following 
heads :  1,  Lincoln,  Leicester,  Cotswolds,  and  other  large 
kinds  weighing  from  9  st.  and  upwards  ;  2,  Southdowns, 
Scotch,  and  other  skins  of  medium  weight ;  and  3,  Skins 
of  small  Welsh  mountain  sheep,  foreign  sheep  slaughtered 
in  this  country,  and  the  numerous  varieties  of  lamb  skins. 

The  larger  stout  sheep  skins  are  usually  split  by  machi- 
nery, the  grain  side  being  used  for  skiver,  and  the  Jlesh 
side  employed  in  preparing  buff  or  "  shamoy  "  leather 
(oiled  leather),  and  in  the  manufacture  of  parchment.  A 
considerable  number  of  the  larger  heavy  sheep  skins  are 
tanned  into  what  are  called  basils,  the  West  of  England 
being  specially  famous  for  its  oak-tanned  basils,  while 
Scotland  and  some  of  our  northern  counties  also  produce 
vast  quantities  of  basils,  which  are  tanned  with  larch  bark, 
and  are  much  used  by  saddlers  for  lining  the  heavier 
leathers.  It  is  believed  that  the  aromatic  odour  imparted 
by  larch  bark  gives  to  the  leather  prepared  with  it  similar 
attributes  to  those  generally  accorded  to  Russian  leather. 
Considerable  numbers  of  the  larger  sheep  skins  are  tawed 
with  alum  and  salt. 

The  medium  weight  skins  are  chiefly  tanned  with  sumach 
for  roans,  a  variety  of  leather  somewhat  resembling  mo- 
rocco, but  wanting  its  peculiar  grain.  These  skins  are 
also  used  for  preparing  leather  used  for  the  rollers  of  cotton 
spinning  machinery.  The  small  sheep  skins  of  Wales  and 
Scotland  and  the  mountainous  districts  of  England  are 
employed  in  the  art  of  tawing,  for  gloves,  shoe  linings,  and 
numerous  other  purposes.  Cape  sheep  and  lamb  skins  are 
very  extensively  used  by  the  manufacturer  of  light  leather, 
being  nearly  equal  to  goat  skins,  and  the  leather  prepared 
from  them  is  largely  used  for  making  dog-skin  gloves,  and 
many  kinds  of  coloured  gloves  exposed  for  sale  as  kid  gloves. 

Treatment  of  the  Skins.— The  skins  are  first  thoroughly 


436  LEATHER  MANUFACTURE. 

washed  in  water,  to  cleanse  them  from  filth  and  dirt,  after 
which  they  are  spread  out  flat,  one  above  another,  with  the 
flesh  side  upward.  Each  skin  is  then  painted  over  with  a  thick 
cream  of  lime  on  the  flesh  side.  The  skin  is  next  doubled, 
with  its  wool  side  outward.  The  skins  are  then  piled  in 
heaps  of  about  twenty  skins,  and  allowed  to  remain  un- 
disturbed from  twenty-four  to  forty-eight  hours,  at  the  end 
of  which  time  the  wool  has  become  loosened,  and  the 
workmen,  unfolding  the  skins  one  by  one,  proceed  to  pull 
the  wool  off,  keeping  the  various  qualities  separate.  When 
the  wool  is  removed,  the  pelts  are  thrown  first  into  water, 
and  afterwards  into  a  pit  containing  a  weak  lime  liquor, 
from  which,  they  are  drawn  once  or  twice  a  day,  the 
liquor  being  stirred  or  plunged  each  time  before  replacing 
them  in  the  pit,  so  as  to  equalise  the  action  of  the  lime. 
They  are  treated  in  this  way  for  the  first  three  or  four 
days,  after  which  they  are  subjected  to  a  stronger  lime 
liquor,  being  repeatedly  drawn  daily  as  before,  and  by  the 
end  of  from  seven  to  ten  days,  according  to  the  season,  the 
skins  are  ready  for  unhairing — that  is,  removing  the  hair 
from  the  shanks  and  other  parts  left  after  the  first  opera- 
tion. In  the  early  part  of  summer,  while  the  wool  is  very 
short,  the  skins,  after  being  shorn  of  the  wool,  are  treated 
somewhat  differently.  They  are  first  thrown  into  water  to 
remove  the  filth,  after  which  they  are  placed  in  lime  liquor, 
being  lifted  once  or  twice  a  day  as  before,  and  then  sub- 
jected to  stronger  lime  liquors,  in  which  they  remain 
until  the  wool  readily  yields  to  the  touch,  when  it  is 
removed  in  the  usual  way.  By  this  treatment  the  value 
of  the  wool  is  impaired,  but  this  in  the  case  of  shorn  sheep 
is  of  little  consequence.  The  wool  is  disposed  of  to  tho 
woolstaplers,  who  cleanse  and  prepare  it  for  the  woollen 
manufacturers. 


CHAPTER  XXXIV. 
PARCHMENT,    VELLUM,  AND  SHAGREEN. 

Preparation  of  Parchment  and  Vellum. — Skins  for  Drumheads.— Sha- 
green.— Fish  Skin,  or  Fish  Shagreen. 

Preparation  of  Parchment  and  Vellum. — The  employ- 
ment of  this  substance  for  writing  purposes  is  of  very  early 
date,  and  is  said  to  have  been  invented  by  Eumenes,  King 
of  Pergamos,  in  Asiatic  Turkey,  about  two  hundred  years 
before  the  birth  of  our  Lord.  In  ancient  times  it  was 
known  as  pergamena,  and  was  used,  on  account  of  its 
durability,  for  writings  of  great  importance,  and  as  a  sub- 
stitute for  the  papyrus,  or  writing  paper  of  the  ancient 
Egyptians.  There  are  two  principal  varieties  of  this  sub- 
stance, which  are  known  in  commerce  under  the  names  of 
parchment  and  vellum,  the  latter  being  prepared  from 
the  skins  of  calves,  kids,  and  still-born  calves  and  lambs, 
and  the  former  from  sheep  and  goats.  In  the  preparation 
of  parchment  and  vellum,  the  manipulation  of  the  skin  is 
much  the  same,  but  in  the  latter  case  somewhat  greater 
care  is  necessary  owing  to  the  very  delicate  nature  of  the 
skins  to  be  treated. 

The  skins  are  washed,  limed,  unhaired,  and  fleshed, 
again  well  washed,  and  then  stretched  either  on  hoops  or, 
in  large  manufactories,  upon  a  wooden  frame  called  the 
herse.  This  is  formed  of  two  uprights  and  two  cross- 
bars, well  joined  together  by  mortising,  so  as  to  form  a 
strong  frame  to  be  fixed  to  a  wall.  The  four  bars  are 
perforated  all  over  with  a  number  of  holes,  to  receive 
tapering  boxwood  pegs,  in  each  of  which  is  a  hole,  as  in 
the  pegs  of  a  violin,  to  receive  the  strings  which  are 


43*  LEATHER  MANUFACTURE. 

employed  in  stretching  the  skin.  A  wooden  shelf  is  fixed 
above  the  /terse  to  support  the  tools  used  by  the  workman. 
To  stretch  the  skin,  skewers  of  various  sizes  are  used, 
according  to  the  size  of  the  piece  of  skin  to  be  secured. 
Six  holes  are  made  in  a  straight  line  to  receive  the  larger, 
and  four  to  admit  the  smaller  pegs  or  skewers.  These 
small  slits  are  made  with  a  tool  like  a  carpenter's  chisel, 
and  the  exact  size  to  admit  the  skewer  ;  the  string  round 
the  skewer  is  fixed  to  one  of  the  bolts  of  the  frame,  which 
are  turned  round  by  means  of  a  key  resembling  a  piano- 
forte tuning  key.  The  skewer  is  threaded  through  the 
skin  while  taut.  Being  thus  prepared  and  the  skin 
well  softened  with  water,  the  workman  stretches  it  power- 
fully by  means  of  the  skewers  ;  he  attaches  the  strings  to 
the  skewers,  and  fixes  their  ends  to  the  pegs,  which  he 
then  turns  with  the  key,  taking  care  not  to  allow  any 
wrinkles  to  be  formed.  It  is  usual  to  stretch  the  skin 
more  in  its  length  than  in  its  breadth.  He  then  takes  a 
fleshing  tool,  which  is  a  double-edged  knife  made  fast  in 
a  double  wooden  handle,  in  both  hands,  and  scrapes  or 
shaves  the  skin  from  above  downwards,  by  which  he 
removes  the  fleshy  matters,  which  are  afterwards  collected 
for  glue-making.  The  herse  is  then  turned  round  from 
the  wall,  and  the  grain  side  of  the  skin  is  then  scraped 
With  the  tool  in  an  inverted  position,  so  as  not  to  cut  the 
grain  of  the  skin. 

The  herse  is  again  turned,  and  the  flesh  side  of  the 
skin  is  next  dusted  over  with  sifted  chalk  or  slaked  lime, 
and  is  then  rubbed  over  in  all  directions  with  a  large 
piece  of  pumice-stone,  previously  rubbed  flat  upon  a  sand- 
stone ;  the  moisture  in  the  skin  is  quickly  absorbed  by  the 
chalk.  When  sufficiently  rubbed  on  the  flesh  side,  the 
skin  is  again  turned,  and  the  grain  side  rubbed  in  the 
same  way,  but  without  the  use  of  lime  or  chalk.  The 
above  operation  is  generally  applied  only,  to  the  better 
qualities  of  parchment  or  vellum.  The  skin  is  then  allowed 
to  dry  upon  the  frame  in  the  shade,  care  being  taken  to 
avoid  sunshine  and  also  frost.  In  very  hot  and  dry 
weather  the  skin  is  damped  with  a  wet  cloth,  to  prevent 


PARCHMENT,    VELLUM,   AND  SHAGREEN.          439 

it  from  drying  too  quickly ;  the  skewers  are  tightened 
after  each  damping. 

When  quite  dry,  the  chalk  powder  is  removed  by  rub- 
bing the  skin  with  the  wool  side  of  a  piece  of  lamb  skin.  It 
is  of  great  importance  in  pumicing  not  to  injure  the  texture 
of  the  skin.  If  the  skins  are  greasy  they  must  be  immersed 
in  the  lime-pit  for  a  week  or  ten  days,  then  stretched 
again  upon  the  herse,  and  afterwards  handed  to  the  scraper, 
who  here  employs  an  edge  tool  of  the  same  shape  as  the 
fleshing  knife,  but  larger  and  sharper.  He  mounts  the 
skin  upon  a  frame  like  the  herse,  but  extends  it  merely 
with  cords,  without  skewers  or  pegs,  and  supports  it 
generally  upon  a  piece  of  raw  calf  skin  strongly  stretched. 
The  tail  of  the  skin  being  placed  towards  the  bottom  of 
the  frame,  the  workman  pares  off  with  a  sharp  knife  any 
considerable  irregularities,  and  then  scrapes  the  outside 
surface  obliquely  downwards  with  the  proper  tools  till  it 
becomes  perfectly  smooth.  Any  remaining  irregularities 
are  removed  with  the  pumice-stone.  This  operation  is 
performed  by  laying  the  rough  parchment  upon  an  oblong 
plank  of  wood  in  the  form  of  a  stool,  the  plank  being 
covered  with  a  piece  of  soft  parchment  stuffed  with  wool, 
forming  a  cushion,  for  the  grinding  operation.  It  is  the 
grain  surface  only  that  requires  pumicing.  The  famous 
Strasburg  vellum  is  prepared  with  very  fine  pumice- 
stones. 

Skins  for  Drumheads. * — The  skins  for  drumheads  are 
prepared  from  the  skins  of  calves,  and  for  kettledrums 
from  asses'  skins.  These  are  treated  in  the  same  way  as 
above.  Parchment  is  usually  coloured  only  green  by  the 
following  process :  In  five  hundred  parts  of  rain  water 
boil  eight  parts  of  cream  of  tartar  and  thirty  parts  of  crys- 
tallised verdigris ;  when  this  solution  is  cold,  pour  into  it 
four  parts  of  nitric  acid.  Moisten  the  parchment  with  a 
brush,  and  then  apply  the  above  liquid  evenly  over  the 
surface.  Lastly,  the  necessary  lustre  may  be  given  with 
albumen  (white  of  eggs),  or  mucilage  of  gum  arabic.  ( Ure.) 

*  The  skins  for  banjos  and  tambourines  are  generally  prepared  from  the 
skins  of  still-born  calves. 


440  LEATHER  MANUFACTURE. 

The  sieves  used  in  powder-mills  for  granulating  the 
gunpowder  are  made  from  parchment  prepared  from  hog 
skins.  English  vellum  is  frequently  made  from  split  sheep 
skins. 

Shagreen. — This  name  is  given  to  a  peculiar  kind  of 
parchment,  and  is  prepared  from  the  skins  of  the  horse, 
wild  ass,  and  camel,  as  follows  :  The  skin  is  freed  from 
its  hair  and  cuticle  by  being  long  soaked  in  water,  and 
after  dressing  with  the  currier's  fleshing  knife  is  sprinkled 
over,  whilst  still  wet  and  stretched,  with  the  seeds  of  a 
species  of  Chenopodium,  which  are  imbedded  in  it  by  strong 
pressure,  and  in  this  state  it  is  dried.  The  seeds  are  then 
shaken  off,  and  the  surface  is  rubbed  or  shaved  down  nearly 
to  the  bottom  of  the  seed-pits  or  indentations ;  it  is  next 
soaked  in  water,  by  which  the  skin  swells,  and  the  recently 
depressed  surfaces  rise  into  a  number  of  minute  promi- 
nences; it  is  then  tawed  with  alum,  and  is  lastly  dyed  and 
smoothed  off,  or  saturated  with  mutton  tallow.  Black  is 
given  to  the  skin  by  means  of  galls  and  copperas,  blue 
with  a  solution  of  indigo,  green  with  copper  filings  and 
sal  ammoniac,  and  red  with  cochineal  and  alum.  Sha- 
green was  formerly  extensively  used  for  covering  the 
cases  of  watches,  spectacles,  and  surgical  instruments. 

Pish  Skin,  or  Pish  Shagreen. — This  is  prepared  from 
the  skins  of  certain  species  of  shark,  which  are  covered 
with  horny  projections  in  lieu  of  scales.  The  skins  are 
stretched  upon  frames  and  dried,  in  which  condition  they 
are  sent  to  market.  When  deprived  of  the  projecting 
spines  they  are  dyed  and  used  for  covering  small  boxes, 
tubes  of  small  telescopes,  &c. 


CHAPTER  XXXV. 
GUT-DRESSING. 

Preparation  of  Cattle  Intestines :  Con tinental  Method.— Goldbeaters'  Skin. 
— Lathe  Cords.— Cords  from  Sheep  Intestines.— Cords  for  Tennis  Bats, 
&c. — Whipcords. — Gut  Strings  for  Musical  Instruments. 

THE  art  of  gut-dressing  consists  in  separating  the  mus- 
cular coat  of  the  intestines  of  certain  animals  from  its 
external  or  peritoneal  covering,  and  from  its  internal 
lining,  or  mucous  membrane,  and  is  divided  into  two 
distinct  branches :  1,  the  preparation  of  the  intestines  of 
oxen  and  cows  to  be  used  in  the  preparation  of  alimentary 
substances,  as  sausages,  polonies,  &c. ;  and  2,  the  prepara- 
tion of  the  intestines  of  sheep  for  the  manufacture  of 
cords  or  strings  for  musical  instruments  and  various  other 
purposes. 

Preparation  of  Cattle  Intestines  :  Continental  Me- 
thod. —  Dussauce  describes  the  workshop  of  the  gut- 
dresser  as  "a  room  about  20  feet  long,  16  feet  wide,  and 
12  feet  high,  with  four  windows.  Around  the  sides  of 
the  room  are  ranged  casks  holding  about  sixty  gallons 
each,  and  in  the  middle  of  the  floor  are  fixed  wooden 
stages  for  attaching  hooks.  A  well  is  usually  sunk  in  the 
yard  to  receive  the  waste  matters  of  the  factory." 

There  are  eleven  distinct  operations  in  gut-dressing,  the 
first  of  which  is — 

Scouring. — As  the  small  intestines  of  oxen  and  cows  are 
received  from  the  slaughter-house  they  are  steeped  in  water 
to  moisten  and  smooth  them,  so  that  the  knife  may  slide 
easily  over  their  surfaces.  One  end  of  the  intestine  is 
now  tied  into  a  kind  of  knot  round  a  hook  to  one  of  the 


442  LEATHER  MANUFACTURE. 

stakes  in  the  centre  of  the  room,  the  hook  being  about  six 
or  seven  feet  above  the  floor.  The  workman  then  grips 
the  depending  portion  between  the  forefinger  and  thumb 
of  his  left  hand,  and  gradually  slides  the  hand  down  along 
the  whole  length  of  the  intestine,  and  follows  its  motion 
by  passing  a  knife,  held  in  the  right  hand,  over  the  sur- 
face, to  separate  the  fat  as  far  as  possible  from  the  outer 
coat.  Another  portion  of  gut  is  treated  in  the  same  way, 
and  so  on  until  the  entire  caskful  has  been  cleaned.  Any 
portions  which  have  been  accidentally  cut  by  the  slaughter- 
man are  laid  aside.  The  fatty  matter  scraped  from  the  gut 
is  well  washed  and  melted,  or  rendered,  as  it  is  termed,  and 
disposed  of  to  the  soapmaker. 

Turning  Over. — The  intestines  are  next  washed  in  a 
large  cask  half  filled  with  water,  and  the  workman  next 
proceeds  to  turn  them  inside  out  by  introducing  a  thumb 
into  the  interior  of  each,  and  working  the  gut  upon  it 
with  the  fingers  until  the  whole  length  is  inverted.  A 
number  of  the  pieces  are  then  tied  together  at  their  ends 
with  a  cord  attached  to  the  edge  of  the  cask,  and  when  a 
sufficient  number  of  inverted  intestines  are  thus  secured 
they  are  ready  for  the  next  operation. 

Putrid  Fermentation. — The  object  of  this  process  is  to 
decompose  the  mucous  lining  and  other  parts  which  have 
to  be  separated  from  the  middle  coat  of  the  intestine,  and 
if  the  operation  is  not  conducted  with  great  care  the  whole 
substance  of  the  gut  will  become  softened  and  rendered 
useless.  The  putrefaction  is  allowed  to  proceed  for  two  or 
three  days  in  summer  and  from  three  to  eight  days  in 
winter,  and  it  is  known  to  have  progressed  far  enough 
when  bubbles  of  gas  are  seen  to  arise  from  the  surface  of 
the  intestines. 

Scraping. — The  pieces  are  first  untied,  then  soaked  in  a 
tub  half  full  of  water.  The  workman  next  proceeds  to 
remove  the  decomposed  mucous  membrane  (which  is  now 
outward),  by  scraping  it  off  with  his  thumb  nails  until  it 
is  completely  removed,  and  he  facilitates  the  process  by 
occasionally  dipping  the  pieces  in  water. 

Washing. — The  intestines  are  put  into  a  tub  nearly  full 


GUT-DRESSING.  443 

of  clean  water,  being  stirred  about  several  times  every  day, 
tbe  water  being  changed  two  or  three  times  a  day,  and 
the  operation  continued  until  the  water  comes  from  them 
perfectly  clear  and  free  from  smell. 

Inflation. — When  thoroughly  cleansed  by  the  foregoing 
operations,  one  end  of  each  piece  is  tightly  tied  by  a  piece 
of  string.  The  workman  next  introduces  into  the  open 
end  a  hollow  cylinder  of  cane  or  reed  about  5  inches  long, 
and  after  making  this  air-tight  by  pressing  the  gut  tightly 
round  it,  he  applies  his  mouth  to  the  cane  tube  and  inflates 
the  gut  b}r  blowing  into  it.  He  then  ties  the  end  below 
the  tube,  and  the  piece  is  ready  for  drying. 

Drying. — As  soon  as  all  the  pieces  are  filled  with  air 
they  are  conveyed  to  the  drying  place,  where  they  are 
laid  out  separately  upon  horizontal  poles  placed  about 
5  feet  from  the  ground,  and  here  they  are  left  until  dry. 
When  thoroughly  dry  they  are  taken  down,  cut  across 
with  scissors  as  near  the  ligatures  as  possible.  They  are 
next  pressed  and  flattened  with  the  hand  to  expel  the 
air. 

Measuring. — The  dried  pieces  are  next  sorted  into  dif- 
ferent sizes,  according  to  the  purpose  for  which  they  are 
to  be  used ;  they  are  then  collected  into  bundles,  and  hung 
in  a  damp  place  previous  to  being  submitted  to  the  next 
process. 

Sulphuration. — When  sufficiently  damp,  the  pieces  are 
next  exposed  to  the  fumes  of  sulphur,  in  a  chamber  about 
5  feet  square  and  6  feet  high.  They  are  first  strung  on 
sticks,  and  if  not  sufficiently  moist  they  are  sprinkled  over 
with  water  from  a  brush  ;  they  are  then  suspended  across 
the  upper  part  of  the  chamber  to  the  number  of  about 
100  bundles.  About  one  pound  of  flowers  of  sulphur  is  then 
put  into  an  earthen  dish  placed  on  the  floor  of  the  room, 
and  upon  this  red-hot  cinders  are  laid ;  the  door  is  then 
quickly  closed,  to  retain  the  sulphur  fumes  within  the 
apartment,  and  every  aperture  is  secured  by  luting  or  by 
glueing  pieces  of  paper  over  them.  After  a  few  hours  the 
door  is  opened  and  the  fumes  allowed  to  escape,  when  the 
pieces  are  found  to  be  bleached  and  deprived  of  all  objec- 


444  LEATHER  MANUFACTURE. 

tionable  odour.  While  still  damp,  they  are  twisted  into 
hanks,  packed  with  camphor,  and  are  then  ready  for 
market. 

Goldbeaters'  Skin.— This  is  prepared  from  the  external 
or  peritoneal  coat  of  the  coscum  or  blind  gut  of  neat  cattle. 
The  workman  separates  and  turns  over  the  part  which 
encircles  the  junction  of  the  pouch  with  the  rest  of  the 
intestines,  and  draws  it  off,  inverted,  from  the  other  coats 
to  the  length  of  25  or  30  inches.  It  is  then  soaked  for  a 
short  time  in  a  weak  potash  liquor,  and  is  next  cleaned 
by  scraping  with  a  knife  upon  a  board ;  it  is  then  soaked 
in  water,  and  afterwards  stretched  upon  a  kind  of  frame 
from  40  to  50  inches  long  and  11  inches  wide.  This  frame 
consists  of  two  uprights  held  together  by  two  cross-bars, 
having  longitudinal  grooves  2J  lines  in  width.  The  outer 
surface  of  the  membrane  is  placed  in  contact  with  the 
upper  part  of  the  frame,  and  it  is  stretched  in  every  direc- 
tion, after  which  it  is  glued  to  its  rim.  Another  mem- 
brane is  then  stretched  over  the  first,  with  its  outer  surface 
upward,  and  secured  by  glueing  round  its  edges.  When 
dry,  the  membranes  are  separated  by  passing  a  knife 
along  the  grooves.  Each  strip  is  then  glued  upon  a 
similar  frame,  but  without  grooves,  and  is  washed  over 
with  a  weak  solution  of  alum,  made  by  dissolving  one 
ounce  of  alum  in  two  quarts  of  water.  When  dry,  the 
surface  is  wiped  over  with  a  sponge  dipped  in  a  strong 
solution  of  fish-glue  in  white  wine,  flavoured  with  clove, 
nutmeg,  or  camphor.  When  this  is  dry  a  coating  of 
white  of  eggs  is  applied,  and  after  again  drying  each  strip 
is  cut  up  into  pieces  5J  inches  square,  which  are  then 
smoothed  under  a  press  and  afterwards  made  up  into 
leaves. 

Lathe  Cords.* — These  are  prepared  from  the  intestines 
of  horses,  cleansed  and  prepared  as  before  described,  and 
the  pieces  are  cut  into  bands  or  strips  of  equal  width  in 
the  following  way  :  A  wooden  ball,  furnished  in  its  lower 
part  with  four  equidistant  cutting  blades,  is  fixed  by  a 

*  Gutta-percha  and  vulcanized  india-rubber  have  greatly  superseded 
gut  cords  for  lathes. 


GUT-DRESSING.  445 

wooden  upright  to  a  bench.  The  end  of  an  intestine  is 
then  drawn  over  this  ball,  and  as  the  gut  is  pulled  down- 
ward it  becomes  divided  into  four  equal  strips.  From  four 
to  eight  of  these  strips,  according  to  the  thickness  of  cord 
required,  are  tied  with  a  peculiar  knot  to  one  end  of  a 
stout  piece  of  cord ;  the  end  is  passed  round  a  peg  inserted 
into  a  hole  in  a  solid  post,  to  the  side  of  which  a  number 
of  pegs  are  attached.  About  ten  yards  from  this  post  is 
another  post,  also  provided  with  pegs ;  over  one  of  these 
latter  the  middle  strip  of  the  cluster  is  bound,  the  other 
end  being  brought  back  and  attached  to  the  first  peg  by 
another  knotted  cord.  The  tied  ends  of  the  strips  are  then 
attached  to  the  wheel  by  a  hook  connected  with  a  whirl, 
which  is  made  to  revolve  until  the  strips  are  sufficiently 
twisted.  The  twisted  end  is  then  kept  stretched  by  attach- 
ing it  to  the  peg,  and  any  projecting  filaments  are  cut  off. 
After  stretching  some  time,  the  cords  are  twisted  again, 
and  the  third  and  fourth  time  this  is  done  by  hand,  being 
rubbed  with  and  drawn  through  a  bunch  of  moistened 
horsehair  each  time  after  twisting,  and  again  stretched 
out  between  the  two  posts.  If  the  cord  is  not  smooth  and 
even  when  the  twisting  is  completed,  it  is  rubbed  with  a 
piece  of  dog  skin.  The  cord  is  then  dried,  but  some  manu- 
facturers expose  it  to  the  fumes  of  sulphur.  The  ends  are 
now  cut  off  and  the  cord  is  rolled  into  a  coil. 

Cords  from  Sheep  Intestines.* — It  is  important  that 
the  intestines  should  be  fresh — that  is,  free  from  decom- 
position. They  are  first  cleansed  from  faecal  matter  and 
washed  ;  they  are  then  taken  to  the  workshop,  where  they 
are  soaked  in  a  tub  of  water  and  deprived  of  adhering  fat. 
The  smaller  ends  are  then  tied  together  and  laid  on  the 
edge  of  the  tub,  while  the  remainder  are  allowed  to  steep 
in  the  water  for  several  days,  the  water  being  frequently 
changed.  The  peritoneal  and  mucous  coats  are  then  re- 
moved by  placing  the  intestines  on  a  bench,  which  slopes 
towards  the  rim  of  the  tub,  and  the  surface  is  scraped  with 
the  back  of  a  knife-blade  to  separate  the  membranes  to 
the  width  of  about  half  the  circumference.  This  is  done 
*  Erroneously  called  catgut. 


446  LEATHER   MANUFACTURE. 

by  pulling  it  off  in  pieces  from  the  smaller  end  of  the 
intestine  towards  the  larger  end.  The  gut  is  next  soaked 
in  water  for  twenty-four  hours,  and  afterwards  scraped 
clean  upon  the  bench  with  the  rounded  back  of  a  knife. 
About  8  feet  of  the  larger  ends  are  now  cut  off  for  use  by 
the  sausage-makers ;  the  remainder  are  cut  into  lengths 
and  stratified  with  salt,  which  is  termed  curing.  After 
remaining  in  the  salt  for  some  days  they  are  soaked  in 
water  for  a  night,  and  next  day  they  are  immersed  in  a 
ley  composed  of  pearlash  8  oz.  dissolved  in  water  4  gal- 
lons. The  ley  is  poured  over  the  intestines,  and  every 
two  or  three  hours  the  liquor  is  poured  off  and  the  intes- 
tines are  examined  to  ascertain  if  they  have  been  suffi- 
ciently acted  upon  by  the  alkali.  They  are  next  drawn 
several  times  through  a  brass  thimble  open  at  both  ends, 
and  then  sorted,  according  to  their  sizes,  for  the  different 
purposes  to  which  they  are  to  be  applied. 

Cords  for  Tennis  Bats,  &c.— These  are  generally  made 
from  intestines  of  inferior  quality,  or  such  as  have  been 
stained  by  incipient  putrefaction.  The  pieces  while  still 
moist  are  sewn  together  with  strips  of  the  outer  mem- 
brane, or  filandre,  each  junction  being  cut  obliquely,  so  as 
to  make  it  level  and  strong.  Three  or  four  of  these  intes- 
tines are  thus  attached  by  strings  to  the  whirl,  and  are 
twisted  as  usual,  after  which  the  cord  is  smoothed  and 
deprived  of  moisture  by  the  workman's  hand ;  it  is  then 
stretched  for  a  time,  when  it  is  again  twisted  and  rubbed 
with  the  bunch  of  horsehair.  The  inferior  kinds  of  cords 
are  prepared  by  twisting  one  gut  along  with  two  or  three 
lengths  of  the  outer  membrane. 

Whipcords. — These  are  made  from  intestines  of  good 
quality,  prepared  as  before,  each  end  being  twisted  sepa- 
rately, since  these  cords  are  seldom  made  from  two  intes- 
tines sewn  together.  The  cord  is  "  sulphured "  once  or 
twice,  and  is  then  smoothed  and  dried,  after  which  it  is 
coiled  in  certain  lengths  for  sale. 

Gut  Strings  for  Musical  Instruments.— Of  all  the 
purposes  to  which  the  intestines  of  animals  are  applied, 
none  is  so  important  as  their  conversion  into  what  is 


GUT-DRESSING. 


447 


commonly  called  catyut,  for  the  strings  or  cords  of 
"  stringed "  instruments,  including  the  whole  violin 
family  and  the  harp.  From  the  earliest  period  Italy  has 
been  most  famed  for  the  production  of  violin  strings  of 
the  finest  quality,  a  reputation  which  she  has  main- 
tained to  the  present  day;  and  though  a  vast  numher 
of  these  strings  are  made  both  in  England  and  various 
parts  of  the  Continent,  the  "  Roman  strings,"  as  they  are 
called,  are  justly  held  in  the  highest  estimation.  It  is  a 
well-known  fact  that  the  membranes  of  lean  animals  are 
much  tougher  than  those  of  animals  in  a  higher  condi- 
tion, and  it  is  to  this  fact  that  the  superior  quality  of  the 
strings  made  in  Naples  is  due,  since  the  sheep  from  which 
the  raw  material  is  obtained  are  exceedingly  small  and 
also  lean.  The  strings  made  from  the  intestines  of  the 
fat  sheep  of  the  London  market  are  well  known  to  be 
greatly  inferior  in  toughness  and  durability  to  those  of 
Neapolitan  make  ;  and  from  the  frequency  with  which  the 
former  break  when  being  tuned  up  to  concert  pitch,  they 
often  cause  much  disappointment,  irritation,  and  incon- 
venience to  musicians. 

Treatment  of  the  Intestines. — The  intestines  being 
cleansed  as  before,  are  steeped  in  the  potash  leys  (clarified 
with  a  little  alum),  progressively  stronger  each  day,  for 
four  or  five  days,  until  they  are  sufficiently  swollen  and 
bleached.  They  are  then  passed  through  the  thimble,  and 
again  cleansed  in  the  ley,  after  which  they  are  washed, 
twisted,  and  sulphured  for  two  hours,  which  operation  is 
sometimes  repeated  several  times.  They  are  next  polished 
with  horse-hair  cords  and  dried.  The  strings  are  known 
to  be  sufficiently  dried  when  one  of  the  strands,  upon  being 
removed  from  its  peg,  shows  no  disposition  to  curl,  but 
remains  perfectly  straight  in  the  position  in  which  it  is 
held.  When  the  strings  have  reached  this  point  they 
are  rubbed  over  with  olive  oil,  cut  at  the  ends,  and 
coiled  up. 

The  violin  fourth  strings,  which  are  covered  with  plated 
copper  wire,  are  neither  sulphured  nor  oiled.  The  string 
to  be  wire-covered  is  cut  off  to  the  length  of  1J  yard ;  one 


448  LEATHER  MANUFACTURE. 

of  its  ends  is  attached  to  the  hook  of  the  wheel  and  the 
other  to  the  ring  of  a  whirl,  which  keeps  the  string 
stretched  by  means  of  a  weight  at  the  end  of  a  cord 
fastened  to  it,  and  passing  over  a  pulley.  The  wire  is 
then  fastened  around  the  string  close  to  the  whirl,  and  as 
the  wheel  is  made  to  revolve  the  string  and  the  whirl 
turn  with  it.  The  workman  supports  the  string  with  his 
left  hand,  and  the  wire  passing  through  his  right  hand 
is  made  to  revolve  around  it  in  close  spiral  turns  until  it 
is  entirely  and  equally  covered  (Dussauce).  The  utmost 
skill  and  dexterity  on  the  part  of  the  workman  are 
required  for  the  manufacture  of  violin  and  harp  strings, 
which  he  can  only  acquire  by  extensive  experience  and 
care. 


CHAPTER  XXXVI. 
GLUE-BOILING. 

Treatment  of  Glue-pieces,  &c. — French  Glue. — Parchment  Gluo. — 
Size. — Glue  Waste. 

Treatment  of  Glue-pieces,  &c. — The  glue -pieces  and 
other  animal  matters  used  in  the  manufacture  of  glue  are 
put  into  a  large  tank  containing  milk  of  lime,  in  which 
they  remain  for  about  two  weeks,  the  lime  being  renewed 
several  times.  They  are  then  taken  out,  with  the  lime  which 
adheres  to  them,  and  spread  out  in  a  layer  two  or  three 
inches  thick  upon  a  sloping  pavement  to  drain  and  dry, 
being  turned  over  by  means  of  prongs  several  times  a  day. 
The  action  of  the  lime  destroys  all  the  tissues,  blood,  &c., 
rendering  them  soluble,  by  which  they  become  separated 
from  the  glutinous  matter,  which  is  thereby  put  into  a 
condition  to  dissolve  more  freely  in  hot  water.  By  ex- 
posing the  lime  to  the  action  of  the  air,  it  loses  its  caus- 
ticity by  attracting  carbonic  acid,  and  is  thus  prevented 
from  acting  injuriously  upon  the  glue  when  the  mate- 
rials are  boiled.  The  glutinous  matters  are  next  put  into 
baskets  and  washed  in  a  stream  of  water,  after  which 
they  are  placed,  while  still  wet,  in  a  flat-bottomed  copper 
boiler,  furnished  with  a  perforated  false  bottom  to  pro- 
tect the  animal  matter  from  being  burnt  by  the  heat  of 
the  fire. 

First  Boiling. — The  copper  is  filled  about  two-thirds 
with  soft  water,  when  the  washed  material  is  introduced  and 
piled  up  above  the  flange  of  the  boiler  ;  the  fire  is  then 
kindled,  and  as  the  heat  increases  the  material  sinks  into 
the  liquid,  and  after  a  few  hours  becomes  completely 
immersed  in  the  liquid.  During  this  time  the  contents 

2G 


450  LEATHER   MANUFACTURE. 

of  the  boiler  are  frequently  stirred,  and  the  whole  boiled 
gently. 

Draining  off  the  Liquor. — The  liquid  is  drawn  off  by  a 
tap  connected  to  the  bottom  of  the  boiler,  and  beneath  its 
false  bottom,  and  the  first,  second,  and  third  liquors,  re- 
presenting different  qualities,  are  reserved  for  glues  of 
proportionate  value,  the  product  gradually  decreasing  in 
value  as  the  boiling  progresses.  It  has  been  proved  that 
gelatine  undergoes  various  changes  of  condition  after  it 
is  dissolved  by  continued  boiling,  and  it  should  therefore 
be  drawn  off  whenever  it  is  sufficiently  strong  to  form  a 
clear  gelatinous  mass  on  cooling,  and  which  will  cut  into 
tolerably  firm  slices  with  a  thin  wire.  This  is  readily 
ascertained  by  putting  a  little  of  the  liquor  in  a  small 
vessel  and  exposing  it  in  the  air  to  cool,  when  in  the 
course  of  a  few  minutes  it  should  gelatinise  ;  if  such  is 
not  the  case,  the  boiling  must  be  continued  for  a  longei 
period.  As  soon  as  the  proper  condition  of  the  liquor  is 
reached  the  fire  is  checked,  and  the  contents  of  the  boiler 
allowed  to  settle  for  about  fifteen  minutes.  The  tap  or 
stopcock  is  then  turned  a  little  and  all  the  liquor  allowed 
to  flow  into  the  settling  copper,  situated  below  the  first, 
and  which  is  immersed  in  a  hot-water  bath  to  keep  the 
fluid  hot. 

Gelatinising. — After  three  or  four  hours  the  clear  liquor 
is  run  off'  into  a  series  of  square  wooden  boxes  slightly 
narrower  at  the  bottom  than  at  the  top.  The  bottoms  of 
these  boxes  are  cross-grooved  to  regulate  the  size  of  the 
squares  of  glue.  These  boxes  are  placed  very  level  on 
the  stone  floor  of  the  apartment,  which  must  be  rendered 
very  clean,  so  that  in  the  case  of  leakage  the  glue  may  be 
recovered.  The  liquid  glue  is  poured  into  the  boxes 
through  a  funnel,  provided  with  a  filter-cloth,  until  it 
reaches  the  upper  rim  of  each  box.  The  apartment  re- 
quires to  be  very  dry  and  cool  to  aid  the  solidification  of 
the  glue. 

Cutting. — If  the  boxes  have  been  filled  overnight,  the 
glue  will  generally  be  sufficiently  firm  to  cut  on  the 
following  morning.  The  boxes  are  then  removed  to  a 


CLUE-BOILING.  451 

well- ventilated  upper  loft,  in  which  the  air  is  admitted 
from  all  points;  they  are  then  carefully  turned  upside 
down  upon  a  table,  previously  moistened  to  prevent  the 
glue  from  sticking  to  it.  The  glue  is  then  loosened  from 
the  sides  of  the  boxes  by  passing  a  moist  long-bladed 
knife  round  the  inner  sides.  The  block  of  glue  is  first  cut 
into  slices  horizontally  by  means  of  a  thin  brass  wire 
stretched  in  a  frame  like  that  of  a  frame-saw,  and  the 
cuts  are  guided  by  rulers  placed  at  proper  distances  to 
suit  the  required  thickness  of  the  glue  cakes.  The 
square  cakes  are  formed  by  cutting  with  a  moist  knife 
through  the  lines  formed  by  the  grooves  in  the  bottom  of 
the  box. 

Drying. — The  gelatinous  squares  are  next  lifted  very 
carefully  and  laid  upon  nets  stretched  upon  wooden 
frames  ;  as  each  frame  is  filled  another  is  placed  above  it, 
to  be  filled  in  its  turn,  and  so  on.  The  frames  are  set 
over  each  other,  with  a  space  of  about  three  inches  be- 
tween, and  upon  small  wooden  pegs  fitting  into  holes  in 
uprights  fixed  round  the  room,  so  that  the  air  may  have 
free  access  on  every  side.  The  frames,  supported  by 
the  wooden  pegs,  slide  to  and  fro  like  a  drawer,  which 
enables  the  workmen  to  shift  them  from  time  to  time, 
to  turn  the  cakes  over,  which  is  done  two  or  three  times 
each  day. 

There  is  no  detail  in  the  manufacture  of  glue  which  is 
so  uncertain  as  that  of  drying  the  jellified  material,  espe- 
cially in  the  earlier  stages  ;  if  the  temperature  of  the 
atmosphere  should  rise  above  a  certain  degree,  the  gelatine 
may  run,  and  trickle  through  the  netting  upon  the  cakes 
beneath,  or  may  become  just  sufficiently  soft  to  firmly 
attach  itself,  when  drying,  to  the  netting,  rendering  it 
necessary  to  plunge  the  net  into  boiling  water  to  discon- 
nect the  cakes  ;  and  even  if  these  untoward  difficulties  do 
not  arise,  the  augmented  temperature  will  render  the  cakes 
so  soft  as  to  put  them  out  of  proper  shape.  Again,  if  the 
gelatine  become  frozen,  the  cakes  are  liable  to  crack,  and 
thus  necessitate  remelting.  In  damp  and  foggy  weather 
the  glue  is  liable  to  become  mouldy  on  the  surface,  while 


452  LEATHER  MANUFACTURE. 

if  the  air  be  too  dry  and  hot,  it  is  likely  to  dry  too  rapidly, 
causing  it  to  crack  in  numerous  places.  The  only  remedy 
for  the  above  evils  is  to  keep  the  flaps  of  the  drying-room 
windows  closed  as  occasion  may  require,  and  if  possible  to 
conduct  the  operation  in  the  spring  or  autumn.  "When 
the  cakes  have  been  dried  upon  the  nets  they  may  still 
retain  a  certain  amount  of  elasticity,  which  would  render 
them  unsaleable  ;  when  such  is  the  case  they  require  to  be 
dried  in  a  stove  by  moderate  heat. 

Glossing. — In  order  to  give  the  cakes  the  bright  glossy 
surface  which  is  characteristic  of  this  article,  the  dried 
cakes  are  dipped  one  by  one  into  hot  water  for  an  instant, 
and  they  are  then  brushed  over  with  a  brush,  also  dipped 
into  hot  water.  The  cakes  are  then  spread  upon  a  hurdle, 
and  are  afterwards  placed  in  the  stove- room  if  the  weather 
be  damp,  until  the  surfaces  are  perfectly  dry,  when  they 
are  ready  for  packing  into  casks  for  sale. 

Second  Boiling. — After  the  first  liquor  has  been  removed 
as  before  described,  fresh  water  is  put  into  the  copper, 
and  the  boiling  continued  until  the  mass  has  a  gelatinous 
appearance,  when  the  liquor  is  drawn  off  by  the  stopcock 
as  before,  and  is  then  submitted  to  the  same  operations  as 
the  first  liquor. 

Third  Boiling. — The  remaining  grounds  are  next  treated 
with  a  fresh  supply  of  water,  or  weak  liquors  containing 
some  gelatine.  The  bottoms,  or  grounds,  are  afterwards 
taken  out  of  the  boiler  and  placed  in  bags,  which  are 
submitted  to  pressure  to  extract  as  much  of  the  liquor  as 
possible. 

The  above  three  boilings  yield  three  different  qualities 
of  glue.  The  first  is  pale  coloured,  and  is  the  most  suit- 
able for  uniting  all  kinds  of  woodwork.  The  second  and 
third  qualities  are  often  preferred,  however,  by  workmen 
who  innocently  believe  that  a  dark-coloured  glue  has  the 
strongest  adhesive  power. 

French  Glue. — This  is  made  from  the  gelatine  of  bones. 
The  bones  are  first  treated  with  hydrochloric  acid,  which 
dissolves  the  phosphate  of  lime,  leaving  the  gelatinous 
substance  of  the  bones  in  a  soft  and  soluble  condition, 


GL  UE-  BOILING.  45  3 

which  is  afterwards  dissolved  and  converted  into  glue. 
The  product  is,  however,  of  very  poor  quality,  and  is 
soluble  in  cold  water — a  proof  of  its  inferiority.  Good 
glue  does  not  dissolve  in  cold  water,  but  is  merely  soft- 
ened by  it. 

Parchment  Glue  is  prepared  from  the  shreds  or  shavings 
of  parchment,  vellum,  white  leather,  &c.,  by  boiling  in 
water;  it  is  nearly  colourless,  and  without  odour. 

Glue  of  inferior  quality  may  also  be  prepared  from  the 
tendons  and  other  offals  of  the  slaughter-house,  but  the 
refuse  of  the  tanneries,  such  as  the  ears  of  oxen,  calves, 
sheep,  &c.,  form  a  better  glue  stock,  while  the  parings  of 
ox  and  cow  hides  are  the  best  of  all  materials  for  glue- 
making. 

Size. — Ordinary  size,  such  as  is  used  in  plastering  and 
other  coarse  work,  is  prepared  from  the  same  materials 
as  common  glue,  but  the  liquid  is  not  evaporated  to  so 
great  an  extent  as  is  requisite  for  the  latter  substance ; 
being  alwaj^s  kept  in  a  soft  condition  so  as  to  be  readily 
soluble  in  water,  the  gelatine  solution  is  made  of  such  a 
strength  that,  when  cold,  it  will  set  into  a  firm  jelly,  or,  as 
it  is  called,  size.  Other  varieties,  of  a  superior  quality, 
are,  however,  prepared  for  manufacturing  gelatine,  for 
thickening  soups,  and  other  domestic  purposes,  from  se- 
lected materials,  such  as  calves'  pates,  &c.  In  preparing 
this  quality  of  size  greater  care  is  taken  to  remove  the 
lime  than  is  necessary  in  ordinary  glue-making,  and  to 
accomplish  this  the  pieces,  after  liming,  are  treated  in  a 
very  dilute  solution  of  hydrochloric  acid.  The  boiling  is 
usually  effected  by  means  of  steam-heat,  and  the  liquid, 
when  in  the  proper  condition,  is  either  run  out  into  small 
casks  for  sale,  or  into  large  vats,  and  when  cold  is  broken 
up  and  packed  in  casks.  For  making  the  finest  qualities 
of  size,  for  use  as  an  article  of  diet,  steam  jacket-pans  are 
employed  in  boiling  the  materials.  The  size  used  by 
paper-makers  is  of  the  best  quality  manufactured  by 
ordinary  glue  makers. 

Glue  "Waste. — The  refuse  left  after  the  final  boiling  is 
thrown  aside  for  manure.  Since  it  rapidly  decomposes, 


454  LEATHER   MANUFACTURE. 

however,  it  soon  becomes  offensive,  rendering  its  removal 
exceedingly  unpleasant  after  about  twenty-four  hours. 
MM.  Leblanc,  of  Lyons,  have  discovered  in  this  refuse 
matter  a  considerable  quantity  of  a  fatty  substance,  which 
can  be  used  in  the  manufacture  of  soap  as  well  as  for 
lubricating  purposes.  It  can  be  extracted  by  means 
of  bisulphide  of  carbon,  petroleum,  benzol,  &c.,  but  sul- 
phuric acid  is  recommended  as  being  cheaper  and  safer 
in  use.  A  vessel  capable  of  holding  from  50  to  100 
gallons,  heated  by  steam  or  otherwise,  may  be  used  for 
the  purpose. 

For  220  Ibs.  of  refuse,  11  gallons  of  water  are  taken  and 
acidified  with  sulphuric  acid,  till  it  stands  at  about  6°  to 
8°  Baume.  The  whole  is  then  boiled,  and  after  a  suitable 
mixing  has  been  effected,  sulphuric  acid  of  48°  Baume  is 
poured  in  by  degrees,  until  a  complete  saturation  has 
taken  place,  or  until  the  fatty  substance  has  been  sepa- 
rated. The  quantity  of  the  48°  acid  varies  according  to 
the  greater  or  lesser  proportion  of  gelatine  in  the  waste. 
It  averages  about  10  per  cent.  This  operation  lasts  about 
two  or  three  hours. 

The  mass  is  then  placed  in  cloths,  each  holding  about 
35  to  45  Ibs.,  and  these  are  placed  under  a  hydraulic  press 
with  a  division  between  each  cloth.  The  fluid  obtained  is 
directed  into  receptacles,  and  the  fatty  substance  on  the 
top  is  removed.  The  pressed  cakes  remaining  are  very 
rich  in  nitrogenous  substances,  which  are  as  effective  for 
manuring  purposes  as  the  refuse  in  its  original  form.  The 
cakes  are  dried,  and  can  then  be  stored  until  required  for 
use. 


CHAPTER  XXXVII. 
UTILISATION  OF  TANNERY   WASTE. 

Spent  Tan.— Curst   and   Court's  Process. — Hide  and  Skin   Cuttings.— 
Hair  Waste. — Lime  Waste.— Glucose  in  Leather. 

Spent  Tan. — When  we  reflect  upon  the  vast  quantify  of 
tan  refuse  that  is  annually  produced  in  the  United  King- 
dom we  cannot  be  surprised  that  many  efforts  should  be 
made — even  by  persons  outside  the  trade — to  turn  this 
waste  material  to  practical  account.  It  had  long  been  the 
practice  at  some  tanneries  to  employ  it  when  dried,  or 
partially  dried  in  the  air,  as  fuel ;  again,  a  considerable 
quantity  has  been,  and  is  now,  used  as  manure.  In  1852 
Mr.  J.  B.  Hoyt,  of  New  Jersey,  conceived  the  idea  of  burn- 
ing wet  spent  tan  in  a  detached  brick  furnace,  and 
succeeded  in  obtaining  sufficient  heating  power  to  drive 
his  machinery  by  its  agency,  and  practically  adopted  this 
method  of  utilising  the  waste  tan  from  that  time.  The 
great  success  of  his  system  created  quite  a  revolution  in 
the  American  tanneries,  and  its  adoption  became  general. 
In  this  country  Messrs.  Huxham  and  Browns  have  con- 
structed a  tan-burning  boiler,  which,  we  believe,  has 
proved  very  efficient. 

Another  and  still  more  important  use  for  spent  tan — 
should  any  of  the  patented  processes  prove  successful — is 
in  the  conversion  of  the  fibrous  waste  into  pulp  for  paper- 
making.  This  would  doubtless  be  the  most  profitable 
purpose  to  which  the  material  could  be  applied  if  an 
effectual  and  economical  method  of  pulping  and  bleaching 
could  be  introduced.  In  1881  Messrs.  Guest  and  Court 
obtained  a  patent  for  converting  waste  tan  into  pulp  for 


456  LEATHER    MANUFACTURE. 

paper-making,  the  abridged  process  of  which  is  given 
below. 

Guest  and  Court's  Process. — The  spent  tan  is  put  into 
a  hopper,  from  which  it  gradually  passes  between,  and  is 
crushed  by,  two  or  more  revolving  rollers,  the  object  of 
which  is  to  open  the  fibres  and  break  up  the  knots  of  the 
waste  material.  The  inventors  prefer  to  feed  the  rollers 
with  the  spent  tan  in  a  semi-dry  state.  The  fibres  being 
thus  separated  to  some  extent,  the  mass  is  introduced  in 
convenient  quantities  into  a  rotary  boiler  or  agitator 
containing  a  solution  of  caustic  soda  in  the  proportion  of 
one-twentieth  part  to  the  water  used.  The  boiler  is  then 
closed,  steam  admitted,  and  the  whole  agitated  by  means 
of  arms  or  cutters  in  the  interior,  and  the  separating  or 
opening  (disintegrating)  process  maintained.  The  mass 
may  be  washed  in  the  boiler  or  in  a  separate  vessel. 
When  it  is  desired  to  bleach  the  mass,  it  is  subjected  to 
the  action  of  bleaching  materials.  In  the  event  of  any 
such  process  becoming  really  practicable,  it  would  then  be 
worth  while  to  keep  spent  bark  separate  from  valonia,  &c. 

Hide  and  Skin  Cuttings. — These  are  commonly  called 
"  glue  pieces/'  and  are  disposed  of  to  the  glue  manufac- 
turers, but  their  value  depends  greatly  upon  the  care 
taken  to  preserve  them  from  decomposition.  This  is  more 
especially  important  when  they  are  to  be  used  for  making 
size  for  paper-making,  since  the  least  smell  or  "  taint " 
would  be  noticeable  in  the  paper,  and  greatly  reduce  its 
value.  It  is  also  very  important  that  the  fine  glues  used 
in  bookbinding  should  be  free  from  objectionable  smell ; 
therefore  it  will  be  well  understood  that  the  value  of  the 
glue  pieces  will  depend  upon  their  not  having  undergone 
decomposition  while  in  the  possession  of  the  tanner. 
When  it  is  borne  in  mind  that  glue  pieces  which  have 
become  tainted  can  only  be  employed  for  making  what  is 
known  as  carpenters'  glue,  their  preservation  from  decom- 
position should  be  a  matter  of  great  consideration  in  order 
to  maintain  their  proper  value. 

[Respecting  the  preservation  of  glue  pieces,  Jackson 
Schultz  makes  the  following  observations :  "  Whether 


UTILISATION  OF  TANNERS'    WASTE.  457 

from  green  or  dry  stock,  the  trimmings  should  be  thrown 
into  weak  lime  as  soon  as  they  leave  the  beam,  and  should 
be  retained  in  this  lime  until  the  hair  will  almost  drop 
off;  when  in  this  condition  they  should  be  thrown  into  a 
revolving  wheel  (tumbler),  or  may  be  put  into  the  hide 
mill,  and  worked  until  all  the  hair  has  been  separated 
from  the  pieces.  If  a  bountiful  supply  of  water  has  been 
allowed  to  run  on  while  the  wheel  or  mill  was  in  operation 
all  the  hair  will  have  worked  off  and  separated  from  the 
pieces,  which  will  then  have  parted  with  so  much  of  their 
lime  as  to  make  them,  when  dry,  flinty  and  hard ;  to 
avoid  this  they  should  be  thrown  back  into  the  lime  for  a 
few  days,  and  again  '  raised.'  Before  they  are  taken  out 
to  dry'  they  should  be  thoroughly  washed.  The  drying 
should  be  in  the  open  air,  and  if  on  a  flat  board  surface 
the  pieces  should  be  frequently  turned.  Care  should  be 
taken  to  wash  off  all  the  loose  lime,  so  that  the  pieces 
may  present  an  attractive  uniform  white  and  clean  sur- 
face. When  they  are  fully  dried,  they  should  be  pressed 
into  uniform  bales  [cakes].  Under  no  circumstances 
should  any  tainted  or  damaged  piece  be  allowed  to  go  into 
the  bale.  Paper-makers  will  use  such  hide  offal  for 
sizing,  and  pay  three  or  four  cents  per  pound  more  for  it 
than  glue-makers  can  afford  to  pay.  Calf  skin  shanks 
and  pates  are  worth  more  for  this  purpose  than  hide 
cuttings,  and  should  always  be  kept  separate." 

The  above  observations  of  a  thoroughly  practical  and 
successful  tanner  should  command  attention,  and  which 
they  will  doubtless  receive,  from  those  who  are  desirous 
of  deriving  the  full  advantage  from  such  valuable  offal  as 
the  trimmings  of  hides  and  skins.  The  cuttings  from . 
neat  cattle  are  more  valuable  than  those  of  the  sheep, 
while  those  from  goats  are  of  less  value  than  the  latter. 

Hair  Waste. — Formerly  cattle  hair  was  only  used  by 
plasterers  to  promote  the  binding  properties  of  mortar, 
but  of  late  years  this  material — especially  calves'  hair — 
has  been  employed  in  the  manufacture  of  cloth,  carpets, 
and  felting.  It  is  of  importance,  therefore,  that  this  waste 
product  should  be  preserved  and  rendered  saleable  by 


45S  LEATHER   MANUFACTURE. 

being  well  cleaned  and  washed.     For  this  purpose    hair 


*C5 

washing  machines  have  been  introduced. 

Lime  Waste. — If  we  bear  in  mind  the  very  small 
amount  of  lime  which  water  is  capable  of  dissolving, 
namely,  only  88'48  grains  per  gallon  at  the  temperature 
of  60°  Fahr.,  the  common  practice  of  putting  the  cleansed 
skins  or  hides  into  what  is  termed  "  weak  lime,"  or  "  old 
lime  " — that  is  to  say,  lime  that  has  been  vised  over  and 
over  again — would  appear  to  be  open  to  objection.  When 
these  old  liquors  contain  little  or  no  caustic  lime  in  solution, 
and  chiefly  carbonate  of  lime  as  the  residuum,  it  is  ques- 
tionable whether  the  cost  of  labour  in  handling  and  loss  of 
time  involved  in  what  may  be  an  inert  process,  would  not 
be  better  applied  to  treating  the  skins  in  really  active 
(that  is,  fresh)  liquors.  The  cost  of  lime  is  but  small,  and 
the  amount  actually  exhausted  in  the  process  of  depilation 
cannot  be  much.  We  venture  to  suggest,  therefore,  that 
economy  would  be  found,  not  in  trying  to  get  a  little  more 
out  of  weak  liquors,  but  in  discarding  them  altogether  so 
soon  as  they  give  evidence  of  inaction.  Again,  the  prac- 
tice of  using  large  proportions  of  lime  in  charging  a  pit 
would  seem  to  be  objectionable,  and  for  this  reason  :  when 
the  lime  has  freely  acted  upon  the  fatty  matters  of,  say, 
100  hides,  the  liquor  becomes  a  solution  of  lime-soap,  and 
it  is  doubtful  whether  in  this  condition  it  is  capable  of 
holding  much,  if  any,  free  lime  in  solution.  If  this  be  so, 
the  liquor  would  become  inoperative  as  a  depilatory,  no 
matter  how  much  lime  might  remain  at  the  bottom  of  the 
pit.  Schultz  urges  that  no  undissolved  lime  should  enter 
the  pit ;  and  although  we  cannot  go  quite  so  far  as  that 
gentleman,  we  do  think  that  a  much  smaller  proportion  of 
lime  than  is  usually  adopted  would  answer  every  purpose, 
and  would  be  far  less  wasteful.  Our  reason  for  differing 
from  the  great  American  authority  is,  that  we  believe  the 
undissolved  lime — which  becomes  diffused  through  the 
liquor  by  the  operation  of  plunging  each  time  the  skins  are 
returned  to  the  pits — has  a  direct  and  powerful  action 
upon  the  animal  tissues,  the  epidermis  and  subcutaneous 
areolar  tissue,  independent  of  the  dissolved  lime,  which,  as 


UTILISATION  OF  TANNERS1    WASTE.  459 

we  have  shown  (p.  117),  only  amounts  to  11 '6  grains  in  each 
pint  of  the  liquor  at  ordinary  temperatures.  When  the 
liquors  are  highly  "  soapy,"  if  we  may  use  the  term,  the 
action  of  the  lime  would  be  retarded. 

The  lime  waste  of  the  tanneries  is  disposed  of  as  manure, 
but  the  waste  liquors  are  not  so  easily  got  rid  of,  since  if 
they  are  suffered  to  run  into  rivers  these  streams  would 
soon  become  uninhabitable  to  the  finny  tribe.  A  small 
quantity  of  sulphuric  acid,  added  to  the  exhausted  lime 
liquors,  would  liberate  the  fatty  acids  of  the  lime-soap,  and 
these  could  be  collected  as  a  scum  from  the  surface.  Jf 
this  were  done  exactly  to  the  point  of  saturation  (that  is 
to  say,  without  excess  of  acid),  the  waste  liquor  would  be 
rendered  innocuous,  and  its  entrance  into  rivers  would  be 
at  all  events  comparatively  harmless.  If  a  small  portion 
of  lime  happened  to  be  present  in  the  waste  liquor,  this 
would  be  thrown  down  as  an  insoluble  sulphate  of  lime. 

Glucose  in  Leather. — It  has  been  stated  that  the 
falsification  of  the  weight  of  leather,  by  adding  glucose, 
or  grape  sugar,  is  carried  on  somewhat  extensively, 
and  the  shoe  trades  are  seeking  protection  from  this 
system  of  fraud.  The  presence  of  glucose  in  leather  may 
be  ascertained  in  the  following  way :  Steep  a  piece  of 
the  suspected  leather  in  a  little  water  for  twenty-four 
hours,  when  the  glucose  will  become  dissolved,  forming  a 
thickish  syrupy  liquid.  Or,  if  two  pieces  of  the  leather 
be  moistened  and  then  placed  together  and  left  for  a  time, 
they  will  be  found  to  adhere  firmly,  which  in  the  case  of 
pure  leather  would  not  occur.  It  is  stated  that  samples  of 
sole  leather  have  been  found  to  contain  from  30  to  40  per 
cent,  of  glucose,  but  this  seems  incredible.  It  is  a 
peculiarity  of  leather  treated  with  grape  sugar  that  after 
being  wetted  it  is  difficult  to  dry. 


46o 


LEATHER   MANUFACTURE. 


FRENCH  METRICAL  OR  DECIMAL  MEASURES  OF  LENGTH. 


Names. 

Eq.  in  Metres. 

Equivalents  in 

English  Inches  at 
32°  Fahr. 

English  Long  Measure  at 
623  Fahr. 

Millimetre    .  . 
Centimetre    .  . 
Decimetre  .... 
Metre     

•001 
•01 
•1 
1- 
10- 
100- 
1000- 
10000- 

•03937 
•39371 
3-93708 
39-37079 
393-70790 
3937-07900 
39370-79000 
393707-90000 

*  ti  .  4     1      * 

§  g    B     £      ,3 

1       0        3-37 
10       2       9-7 
109       1        1-078 
4     213       1      10-3 
6     1     156       0       9-17 

Decametre    .  . 
Hectometre  .  . 
Kilometre  .... 
Myriametre  .  . 

%*  The  standard  unit  of  the  above  table  is  the  metre,  which  has  been 
determined  to  be  39-37079  inches  at  32°  Fahr.  (Capt.  Kater) ;  the  Eng- 
lish foot  is  taken  at  62°  Fahr.  The  true  length  of  the  metre,  reduced  to 
the  latter  temperature,  is  39-370091  English  inches,  a  number  which 
varies  from  that  in  the  table  only  at  the  fourth  decimal  figure.  It  will  be 
perceived  that  the  principle  of  nomenclature  adopted  in  applying  the 
names,  was  to  prefix  the  Greek  numerals  to  the  decimal  multiples,  and  the 
Latin  numerals  to  the  decimal  subdivisions. 


FRENCH  METRICAL  OR  DECIMAL  MEASURES  OF  VOLUME. 


Names. 

Eq.  in  Litres. 

Eq.  in  English 
Cubic  Inches. 

Equivalents  in  English 
Measures. 

Millilitre  .... 
Centilitre  .... 
Decilitre    .... 
Litre  

•001 
•01 
•1 
1- 

•0610 
•6103 
6-1028 
61-028 

i  1  §  1  I 

16-9 
2     49- 
3     4     10-36 
1   15     1     43'69 

Decalitre  
Hectolitre  .... 
Kilolitre    
Myrialitre     .  . 

10- 
100- 
1000- 
10000- 

610-28 
6102-8 
61028- 
610280- 

2     1  12     1     16-9 
22     0     1     4     49- 
220     0  16     6     40- 
2201  (~275|  bushels). 

%*  The  standard  unit  in  the  above  table  is  the  litre,  or  the  cube  of  the 
one-tenth  of  a  metre.  The  French  centiare  contains  1  square  metre ;  the 
are,  100  ditto;  the  hectare,  10,000  ditto.  The  old  Paris  pint  is  equal  to 
1-678  English  imperial  pint. 

ttf  The  capacity  of  solids  and  aeriform  fluids  is  taken  in  cubic  inches 
or  feet,  in  England.  In  France,  the  stere,  or  metre  cube,  equal  to  35-31658 
English  cubic  feet,  is  the  standard  unit. 


WEIGHTS  AND  MEASURES.  461 

WEIGHTS  AND  MEASURES  OF  THE  METRICAL  SYSTEM. 
From  the  British  Pharmacopoeia. 

WEIGHTS. 

Milligramme  =.  the  thousandth  part  of  one  gramme,  or  0-001  gramme 
Centigramme  =  the  hundredth      ,,  ,,  ,,         0-01 

Decigramme  =.  the  tenth  „  ,,  ,,         0-1 

Gramme  =.  weight  of  a  cubic  centimetre  of  waler  at  4'  C.  1  '0 
Decagramme  —  ten  grammes  .....       10-0 
Hectogramme  =.  one  hundred  grammes  .         .         .     100-0 
1  Kilogramme  =  one  thousand  grammes    .         .         .  1000-0  (1  kilo  ) 

MEASURES  OP  CAPACITY. 

1  Millilitre  —  1  cubic  centimetre,  or  the  measure  of  1  gramme  of  water. 

1  Centilitre  =  10  „  „  ,,  10       „  „ 

1  Decilitre  =100  „  „  „  100     „  „ 

1  Litre         =1000  „  „  „  1000  (1  kilo.) 

MEASURES  OP  LENGTH. 

1  Millimetie  =  the  thousandth  part  of  one  metre,  or  0-001  metre. 
1  Centimetre  =  the  hundiedth        „  „  0-01         „ 

1  Decimetre  =  the  tenth  „  „  01  „ 

1  Mfetre  =  the  ten-millionth  part  of  a  quarter  of  the  meridian  of 
the  earth. 


INDEX. 


A  BIES  CANADENSIS,  85 

•Li-      Abusive  treatment  of  raw  hides, 

53 
Acacia,  83 

arabica,  84 

catechu,  84 

dealbata,  8G 

decurrens,  85 

horrida,  84 

melanoxylon,  84 

mollissima,  84,  85 

nilotica,  85 

pyeantha,  83 
Acetate  of  iron,  281 

of  lime,  308 
Acetic  acid,  17,  301 

fermentation,  142 
Acid,  acetic,  17,  301 

carbolic,  66 

catechuic,  75 

catechu-tannic,  14 

chromic,  262,  324 

ellagic,  62,  413 

gallic,  14,  57 

properties  of,  58,  GO 

gallo-tannic,  43 

hydrochloric,  45,  95,  325 
chromic,  349 

k  ram  eric,  80 

malic,  65 

in  eta-gal  lie,  60 

nitric,  55 

oxalic,  47,  301 

phosphoric,  301 

pyrogallic,  14,  50,  61 

pyroligneous,  65 

quercitannic,  101 

stearic,  312 

sulphuric,  45,  95,  174 
bate,  141 

tannic,  11,  50,  301 

Badviland  Lienders'  process 
for  preparing,  47 


Acid,  tannic,  Berzelius'  process,  44 

Bouillon- Legrange's    pro- 
cess, 45 

Coez's  process,  47 
Deyeux's  process,  46 
Dize".s  process,  45 
Kohlrausch's  process,  48 
Merat-Guillot's  process,  45 
Pelouze's  process,  43 
Proust's  process,  46 
Schering's  process,  46 
Serturner's  process,  46 
properties  of,  49 
pure,  51 
reactions  of,  52 
tartaric,  65,  301 

Acids,  depilation  by,  129 
iron  blueing,  *14 
greening,  14 

Acrpclin,  365 

Action  of  tannic  acid  on  gelatine,  13 

Adurla,  84 

African  gallnut,  87 

Air-heated  tumblers,  378 

Albumen,  27 

Alcamo  sumach,  78 

Alchemilla  vulgaris,  49 

Alcoholic  extract  of  logwood,  304 

Alder,  84  ;  bark,  54,  87 

Aldrich's  tanning  process,  171 

Aleppo  nutgalls,  53 
pine,  84 

Algarpbiall,  84 

Alkali,  caustic,  53 

Alkaline  sores,  133 

Alligator  skins,  42,  432 

copying  by  electrotype,  432 

Almardelboom,  84 

Almond  oil,  311 

sweet,  311 

Alnus  glutinosa,  84 

Alum,  218 

and  salt,  treatment  with,  308 


ERRATA   IN  INDEX. 

Page  4G2,  column  1,  lino    2,  for  '  hides  '  read  '  hide.' 
„    4G2,       „        1,     „      3,  far  '  53  '  raid  '  35.' 
,,    4G3,       „        1,     ,,    24,  for '  Analysation  of  catechu  '  m«d '  Analysis 

of  catechu.' 

,,     463,      ,,        1,  After  I.  24,  insert  '  Analysis  of  tannins,  91.' 

,,     404,      ,,        1,     „    52,  /or  '  vegetable  '  read  '  enamel.' 
,,    464,      ,,        1,     ,,    56,  for  'setting  for'  read  'setting  in.' 
„    464,      „        2,     „    14,  delete  '  Blunt  tools,  140.' 
„     465,      „         1,     „    23,  for  'fawing'  read  'tawing.' 
„     465,      „         1,     ,,    25, /or  '  for,  348,'  read  '  for  chrome,  348.' 
,,     465,      ,,         1,     „    48,  for  '  analysation  '  read  '  analysis.' 
„     465,      ,,        2,     „    19,  after  '  91 '  insert  '  104.' 
,,     466,      ,,         1,     ,,    29,  for  '  analinc '  read  '  aniline.' 
„    468,      „        1,     „      2,  for  '  337,345,  346,  354'  read  '304,  337,  345, 

346,  354.' 

„     468,      „        1,  After  1 46,  wserJ'I.A.L.T.C.  method,  104.' 

„     468,      „        2,     „    21,  for  « fellmongering,  434  '  read  '  fellmonger- 

ing,  287,  434.' 

„     468,       „        2,     ,,    24,  for  '  ascetic  '  read  '  acetic.' 
,,    469,       ,,        2,     ,,    35,  for  'one-  and  two-bath  methods'  read'  one- 
bath  method.' 

„     470,       „         2,     ,,    26, for  'stocking, 400,' read  'stocking,  111,400.' 
„    471,       „        1,     „    11, for    'Illustration   of    the  skin,   86,'  read 

'  Illustration  of  the  skin,  26.' 

„     472,       „        2,     ,,    25,  for  '  shamoy,  39,'  read  '  chamois,  39,  357.' 
„     472,       „        2,     ,,    46,  for  '  power '  read  '  process.' 
„    474,       „        1,  After  I.  26,  insert  '  I.A.L.T.C.  method  of 

estimating  tannin,  104.' 
„    480,       „        2,     „    20,  /or'  Striker.Priestman's, 407,' read1  Striker, 

Priestman's,  165,  407.' 
„     481,       „        2,  After  I.  33,  insert  '  I.A.L.T.C.  method  of 

estimating,  104.' 
„     484,       ,,        1,     ,,      8,  for  '  graining  in  after,  382,'  read  '  graining 

after,  382.' 


WATT'S  'LKATHER  MANUFACTURE.' 


CM    "'HE 


UNIVERSITY 


INDEX. 


463 


Alum  dressing,  307,  314,  317 
Alumina,  47 

chromate  of,  175 

sulphate  of,  170 
Aluming,  308,  319 
Aluminium  chromate,  2C3 
Amber  varnish,  298 
Amboyna  kino,  75 
American  bleaching  processes,  270 

method  of  drying  the    tanned 
butts,  156     ' 

pear  lash,  176 

pendulum  roller,  167 

perseverance  and  ingenuity,  323 

rocker  handler,  154,  242 

tanning,  228 

trade  in  leather,  372 

turret  drier,  159 

union  splitting  machine,  322 
Ammonia,  119 

carbonate  of,  45,  141 
Ammoniacal  salts,  255 
Ammonium,  chromate  of,  2G3 
Aualysation  of  catechu,  75 
Anatto,  382 
Aniline  colours,    dyeing  with,   300, 

337,  345,  34(5,  354 
dyeing  with  pure,  304 
in  glove  dyeing,  303 
Animals'  skins,  classification  of,  28 
Anopterus  glandulosa,  86 
Ant:fermeuts,  151 
Antigalline,  67 
Apricot-bark,  54 
Arabic  gum,  340,  439 
Arctium  lappa,  49 
Arctostaphilos  uva  ursi,  84 
Areameter,  Connolly's,  430 
Areca  catechu,  84 
Areolar  tissue,  23,  26 
Argol  bath,  175 
Arm-stake,  342 

board,  382 
Arnica  montana,  49 
Arok  kenema,  84 
Arrasa,  84 

Arsenic  limes,  depilation  by,  329,  330 
Artificial  tannin,  55 
Aru  mata,  84 
Asacum,  84 
Ash-bark,  54 

ley,  276 

soda.  234 

Ashes,  wood,  219,  253 
Ashing,  253 
Asphodel  plant,  47 
Asi.idospermiiui  quebracho,  77,  86 


Ass  and  mule  hides,  38 
Asses'  skins,  439 
Atherosperma  moschata,  86 
Avens  root,  53 
Avicennia  nitida,  84 
Avicenuica  tormeutosa,  86 

BABOOL,  84 
Badvil  and  Lienders'  process  for 

preparing  tannic  acid,  47 
Balsamo,  84 
Bullatschano    and     Trenk's    process, 

174 

Bunksia  australis,  85 
Baramalli,  or  pump  wood,  84 
Barium,  chloride  of,  2G3 
Bark,  alder,  54,  87 

apricot,  54 

ash,  54 

beech,  54 

birch,  54 

cinchona,  49 

common  willow,  21 

cork-iree,  72 

elm,  54 

examination  of,  89 

extract  of,  245 

grinding  the,  237 

harvesting,  72 

hazel,  54 

horse  chestnut,  49 

iron,  85 

kermes  oak,  85 

larch,  54 

mills,  405 

mimosa,  54,  83 

oak,  21,  68,  143 
tanning,  143 

old  oak,  53 

sassafras,  54 

sycamore,  54 

willow,  54 

winter's,  55 

young  oak,  53 
Barking  of  trees,  71 
Barkometer,  90 
Barks,  68 
Barley,  294 

dressing,  294 
Barley-meal,  294 

bating  with,  141 

Baron's  process  of  quick  tanning,  219 
Basic  sulphate  of  iron,  261 
Basils,  39,  414,  435 

oak-tanned,  435 
Bate  or  grainer,  139 

sulphuric  acid,  141 


(    UNIVERSITY   I 


INDEX. 


Bath  dyeing,  301 

sumac,  388 
Bating,  139,  225,  332 

lactic  acid  for,  142 

Turnbull's  process,  141 

with  barley-rmal,  141 

Warrington's  process,  141 
Battery,  48 

Beabejum  stellatum,  84 
Beam,  124,  3G9 

fleshing  on  the,  283 

house,  124 

knife,  French,  2.°>6 
German,  230 

unhairing  on  the,  124 

work,  236 

working  on  the,  124 
Beamsman  or  shaver,  375 
Bearberry,  84 

Beck's  process  of  depilation,  136 
Bell  Stephens'  method  of  estimating 

tannin,  92 
Bell's     process    of     quick    tanning, 

219 
Belt  leather,  33 

or  crop  leather,  226 
Bengal  catechu,  53,  75 
Bennet,  herb,  17 
Benzine,  263 
Benzol,  454 
Berzelius'  process  for  preparing  tannic 

acid,  44 
Betel,  84 
Bttula  alba,  84 
Betuline,  2«2 

Bez  and  Sons'  process,  8,  192 
Bichromate  of  potash,  266 
Birch,  84 

bark,  54 

oil,  distillation  of,  282 

oil  of,  282 

tar  oil,  265 
Bisulphide  of  calcium,  depilation  by, 

132 

Bitartrate  of  potash,  175 
Black  dye,  300,  339 

for  chrome  leathers,  339,  340, 
353 

glace  manufacture,  327-344 

grain,  high  shoes,  396 

Russia  leather,  281 

vegetable,  297 

wattle,  84 

wood,  84 
Blackthorn,  54 
Blacking  and  setting  for  currying, 

OvV 


Bleaching  leather,  269,  362 

processes,  American,  270 
Blocking  boot-fronts,  397 

machine,  397 
Blood  wood,  84 
Bloom,  413 
Blue  dye,  300 

galls,  73 

gum,  84 

Prussian,  297 

Saxon,  300 

Blue-backing,  337,  351 
Blueing,  iron  tannin,  13 
Blunt  tool,  110 
Boa  constrictor,  432 
Bohemian  olive,  54 
Boiler,  tan-burning,  455 
Bombay  catechu,  21,  53,  75 
Bombax  malebarica,  85 
Bone  gelatine,  452 
Boomah,  84 

Boot-fronts,  blocking,  97 
Borate  of  zinc,  264 
Bot,  or  gadfly,  31 
Bottles,  skin,  5 
Bottom  sizes,  383,  384 
Bouillon-Legrange's  process  for  pre- 
paring tannic  acid,  45 
Bourdon  scourer,  155,  413 
Bower,  343 

Box-calf,  manufacture  of,  348-356 
Brain's   process   for   soltming   dried 

hides,  111 
Bran  drench,  308,  316 

dressing,  296 

liquor,  296 

steep,  318 
Branding,  31 
Bran  r.  ing,  308 
Brazil  wood,  277 
Breakers,  309 
Breaking,  307 
Brined  hides,  37 
Brokers,  buyers',  373 
Brown  soap,  391 
Brysonima,  85 
Bucida  buceras,  84 
Buck  skin  dressing,  366 

tallow,  396 
Buff  leather,  38,  363 

machine,  390 

process,  363 
Buffalo  hides,  38 
Buffs,  polishing,  38 
Burbidge's  tanning  process,  203 
Burette,  94 
Butea  frondosa,  76,  84 


INDEX. 


465 


Butea  gum,  53 

kino,  84 

superba,  85 
Butt,  28,  120 

dressing,  388 

kip,  setting  machine,  380 

tanning,  143 

Butts,     tanning     for    sole    leather, 
143 

currying  kip,  373 

drying  the  tanned,  150 

sole,  406 
Buyers'  brokers,  373 


ri/KSALPINIA,  86 
vJ  coriaria,  84 

Calcei  mullei,  Komnn,  6 
Calcium,  oxide  of,  117 

bisulphide  of,  132 
Calf  kid,  311 

drying,  317 
for  uppers,  314 

skins  for  memel,  295 
fawing,  317 
one-  and  two-  bath  methods 

for,  348 

Calves'  skins,  38 
Camata,  or  camatina,  81 
Camel  skin,  440 
Cape  lambskins,  435 

sheepskins,  435 
Carapa  guianensis,  84 
Carbolic  acid,  67,  343 
Carbonate  of  ammonia,  45 
lead,  45 
lime,  117 
potash,  40 

Carpenters'  glue,  450 
Carpnn  brevifolium,  84 
Casali's  process,  109 
Cascara,  84 
Cashew,  74 

Cassia,  49  ;  auriculata,  86 
Castanea  vesca,  84 
Casuarina  quadrivalvis,  80 
Catechine,  75 
Catechu,  17,  84 

acacia,  74 

analysation  of,  75 

Bengal,  53,  75 

Bombay,  21,  75 

Indian,"  75 

Malabar,  75 

Peru,  53 

Catechu-tannic  acid,  14 
Cattchuic  acid,  75 

2 


Catgut,  447 

Cattle  intestines,  prepnration  of,  Con- 
tinental method,  441 
Caustic  alkali,  52 
lime,  115 

soda,  depilation  by,  131 
Celery  pine,  84 
Centauria  cyanus,  49 
Cevil,  84 
Chamois  glove  leather,  362 

leather,  39.  357,  361,  303 
imitation,  40 
manufacture,  357-363 
Charcoal,  depilation  by,  133 

skins,  colouring,  362 
Checking  or  preventing  gallic  fermen- 
tation, 64 

Chemical  methods  of  estimating  tan- 
nin, 91 
tanning,  260 
Heinzerling's  process,  262, 

263,  324 

Knapp's  processes,  261,  321 
Schultz's  process,  324 
Vanderstraaten's      process, 

266 

theory  of,  11 
Chcnopodium,  440 
Cherry-tree,  84 
Chestnut,  84 

extract,  77 
Spanish,  21 
Chinese  nut-galls,  53 
Chloride  of  barium,  263 

potassium,  191 
sodium,  263 
sulphur,  265 
tin,  46 
zinc,  264 
Chlorine,  24,  97 
Chromute  of  alumina,  175 
magnesia,  263 
potash,  262 
soda,  262 

Chromates,  soluble,  262 
Chrome  leather  dyeing,  336,  338,  344- 

347 

history  and  technique,  323 
manufacture,  323-347 

machinery,  415,  419- 

430 
trade     revolutionized 

by,  323,  400 
liquors,  334,  349,  350 
tanning,  334,  349 
Chrome-oxychloride,  349 
Chroming  operations,  334 


466 


INDEX. 


Chrome  processes,  Heinzerling's,  202, 

263 
Schultz's,  324 

process,  popularity  of,  372 

industry,  385 
Chromic  acid,  263 

tannage,  principle  of,  324 
Chrysene,  263 
Cinchona  bark,  49 
Cinnamon,  49 
Classification  of  sheepskins,  435 

skins  of  animals,  28 
Cleansing  and  washing  hides,  224 

raw  hides,  109 
Clearing  stone,  369 
Clove,  444 
Cloves,  55 
Coal-tar  dyes,  300 
Coccoloba  uvifera,  86 
Cochineal,  289 
Cod  oil,  378,  383,  384 
Coecum,  444 
Coez's  process  for  preparing  tannic 

acid,  47 
Cold  sweating,  129 

of  hides,  231 
Colophony,  265 
Colouring  chamois  skins,  362 
Colours,   aualine,  dyeing  with,   300, 

337,  345,  346,  354 
in  glove  dyeing,  303 

pure  aniline,  dyeing  with,  304 
Columbian  kino,  76 
Compo,  348 
Composition,  396 

for  tanning,  253 

of  the  skin,  27 
Common  willow-bark,  21 
Condition  of  hides  and  skins,  28 

of  raw  hides,  108 
Connolly's  areameter,  432 
Continental  method  of  liming,  120 

method  of  preparing  cattle  intes- 
tines, 441 

method  of  preparing  glove-lea- 
ther, 313 

successful    use   of    corichrome, 

346 

Conveyors,  161,  406 
Copal  varnish,  298 
Copperas,  51,  300 
Copper  filings,  440 

sulphate  of,  264 

vitrol  of,  305,  353,  354 
Coppice  oak,  70 

Copying  crocodile  and  alligator  skins 
by  electrotype,  432 


Cordova  leather,  288 

Cords,  lathe,  444 

Cords  for  tennis  bats,  <tc.,  446 

from  sheep  intestines,  445 
Coriaria  myrtifoli<»,  79 

ruscifolia,  86 
Corichrome  mordants,  346 
Corin,  350 

Corium,  or  true  skin,  23 
Cork-tree,  84 

bark,  72 

Cornus  sanguinea,  54 
Cortex,  89 

Corrosive  sublimate,  65 
Cost  of  tanning,  Schultz  on  the,  272 
Cotswold  sheepskins,  435 
Count      Kartstoffs      description     of 

Russian  leather  manufacture,  277 
Couruda,  84 
Cowhides,  split,  currying,  396 

for  brown  bags,  396 
Cox's  tanning  process,  198 
Crab  wood,  84 
Cream  of  lime,  436 
Crepida,  Roman,  6 
Crocodile  and  alligator  skins,  431 

copying  by  electrotype,  432 

and  serpent  skins,  42 
Crocoxvlon  excelsum,  86 
Crop  leather,  226 
Cross-grained  roller,  396 
Crosse's  process  of  tanning  by  electri- 
city, 258 
Crust  goods,  317 
Crutch  stake,  317 
Crystallised  verdigris,  439 
Cube  gambier,  77 
Curmpuay,  84 
Currying,  368 

calf-skins  for  memel,  395 

composition    for    stuffing,   379, 
380 

kip  leathers,  371 

levant  leather,  392 

preparation  of  size  for,  383,  384, 
385 

satin  or  glove  shoe  leather,  385, 
391 

shop,  369 

split  cow-hides,  396 

various  leathers,  395 

waxed  calf-skins,  395 
Curriers'  knife,  317,  370 
Cutch,  74,  81 
Cuticle,  11,  23,  26 
Cutis,  11,  23,  26 

vera,  23,  26 


INDEX. 


467 


Cutting  (glue  boiling).  450 
Cuyaina,  84 
Cynips,  43,  73 

DANISH  quick  tanning  process,  221 
Davy,  Sir  II.,  on  Scgti.n's  theory, 

19 
Davy,  Dr.,  on  the  nction  of  lime  on 

animal  matter,  121 
Davy's  method  of  estimating  tannin, 

92 
Dead  Sea  apples,  73 

vat,  120 

Do  Bock's  tanning  process,  19G 
Deer  skins,  41 

tallow,  39G 
De^ras,  337,  379,  352 
Dehairing,  115,  329,  330 
De-liming,  332 
agents,  332 
Dennis's  tanolin,  349 
Dentelaria,  84 

Deflation,  Beck's  process,  13G 
by  acids,  129 

arsenic  limes,  329,  330 
bisulphide  of  calcium,  132 
caustic  soda,  131 
charcoal,  133 
lime,  115,  329,  330 
machinery,  402 
saccharine  matter,  131 
sulphide  of  sodium,  133,  330 
or  nnhairing  skins  and  hides,  1 15 
Palmer's  process,  134 
by  sweating,  128 
De  mond  s  tanning  process,  202 
Determination  of  tannin  by  specific 

gravity,  89 
Dextrine,  303 
Doyeux's  process  of  preparing  tannic 

acid,  4G 
Dialysis,  49 

Dietz's  process  of  quick  tanning,  217 
Diospyros  glutiuosa,  85 
Diplolepsb,  43 
Disintegrators,  405 
Distillation  of  birch  oil,  282 
Divi  divi,  54,  82,  84 
Dize's  process  for  preparing  tannic 

acid,  45 

Dog-skin  glove?,  435 
wood  berry,  303 
Donzeri  sumach,  79 
Doomboom,  84 

Drake's  tanning  process,  8,  207 
Drawing  off  the  liquor  (glue-boiling), 
450 


Drench,  bran,  308,  31G 
Drenching,  307,  31G,  358 
Dressing,  alum,  3U7,  314,  317 

barley,  294 

bran,  29G 

buck  skin,  3CG 

red,  295 

white,     Morfit's     remarks     on. 

295 

Dressing  leather,  410 
Dried  hides,  30,  110 

softening,  110 

salted  hides,  31 
Drumheads,  skins  for,  439 
Drum-stuffing,  377,  tt78 
materials,  378 
tumbler,  375,  377 
Dr.  Ure's  Views  on  quick  tanning, 

213 
Dry  distillation,  282 

salted  hides,  112 
Drying  310,  317 

black,  339 

calf  skins,  317 

(glue-boiling),  451 

(gut-dressing),  443 

loft,  157 

oil,  297 

the  tanned  butts,  15G 
Dubbin,  377,  384 

Duplex  unhairiug  and   fleshing  ma- 
chine, 315 

Dussauce  on  Seguin's  theory,  1C 
Dussauce's  observations  on  quick  tan- 
ning, 215 
Dust,  emery,  387 
Dye,  black,  300 

blue,  300 

calf-skins,  353 

goat  skins,  339 

green,  300 

olive,  300 

puce,  300 

red,  299 

sulfamine,  345 

violet,  300 

yellow,  300 
Dyeing,  318 

aniline  colours  in  glove,  303 

bath,  301 

chrome  leather,  33G 

fancy  shades,  344 

glove-leather,  303 

kid- leather,  300 

leather,  299 

Morocco  leather,  299 

on  a  flat  surface,  302 


468 


INDEX. 


Dyeing,  with    aniline    colours,    300, 

337,  345,  34(5,  354 
logwood  and  hemolin,  337 
pure  aniline  colours,  304 

Dyes,  coal-tar,  300 

EAST  India  kips,  37,  392 
Egging,  309,  318 
Elaeocarpus  dentatus,  85 
Elder,  54 
Elderberry,  303 
Electricity,  tanning  by,  254 

tanning  by,  Crosse's  process,  258 
Gaulard's  processes,  255,  256 
Meriten's  process,  257 
Ward's  process,  254 
Electrotype,   copying    crocodile    and 
alligators'  skins,  &c.,  by,  432 

copper  rollers,  432 

process,  431 

Elk   skins,    Indian   method   of    pre- 
paring, 268 

Ellagic  acid  (bloom),  62,  413 
Elm-bark,  54 
Emblica  officinalis,  81 
Embossed  leather,  7,  430 
Embossing  leather,  393,  430 

machines,  414,  431,  433 
Emery  dust,  387 
Emulsion  or  paste,  309 
Enamelled  leather,  293 
English  oak,  70 
Eosine,  302 
Epidermis,  18,  23,  89 
Epsom  salt-:,  196 
Erodin,  332 
Erythrosine,  303 
Essence  of  turpentine,  181 
Estimation  of  tannin,  88 

Bell  Stephens'  method,  92 

by  barkometer,  90 

by  chemical  methods,  91 

Casali's  process,  103 

Davy's  method,  92 

determined  by  specific  gravity, 
89 

Hammer's  method,  93 

Lowenthal's  method,  94 

Mr.  Hewitt  on  Lowenthal's  me- 
thod, 97 

Procter  on  do.,  100 

Ramspacker's  method,  102 
Eucalyptus  globulus,  84 

resinifera,  76,  85 

leucoxylon,  87 
Eugenia,  maire,  86 
Examination  of  bark,  89 


Exocarpus  cupressiformus,  84 
Extinction  of  wax  leather,  372 
Extract,  chestnut,  77 

hemlock,  77 

Hungarian  larch,  77 

larch,  77 

mangrove,  80 

oakwood,  77,  377 

of  bark,  245 

quebracho,  77 
Extractive,  18,  213,  222 
Extracts,  tanning,  74 

FAGUS  CUNNINGHAM!,  85 
Menziesii,  86 
Fat-liquoring    chrome    leather,    337, 

345,  351 

Fat-liquors,  337,  338,  362,  363 
Feeding  of  leather,  20,  214 

the  skin,  149 
Fellmongered,  287 
Fellmongering,  434 
Fellmongers,  287 
Fells,  287 
Fermentation,  ascetic,  142 

acetous,  205 

putrefactive,  128 

putrid,  442 
Ferric  acetate,  14 

salts,  14 

sulphate,  14 
FibrilliE,  25 
Fibrin,  17,  18 
Fig  bath,  288 
Filandre,  446 
Finishing,  381 

chamois,  361 

glazed  kid,  341 

machinery,  406,  423 
First  boiling  (glue),  449 

English  patents  for  tanning,  1G9 
Fish,  dog,  345 

glue,  446 

oil,  311 

shagreen,  440 

skin,  or  fish  shagreen,  440 
Flaming,  291 
Fleshing,  124 

and  unhairing,  283 

by  machinery,  315,  831,  404 

knife,  115,  125 

on  the  beam,  283 
Flesh  splits,  289 
Flint  hides,  30,  110 
Formic  acid  for  bating,  142 
French  beam-knife,  236 

glue,  452 


INDEX. 


469 


French  kid  gloves,  41 
leather,  310 
tannage,  383 
French  metrical  or  decimal  measures 

of  length,  460 
metrical  or  decimal  measures  of 

volume,  460 
Fri/ing,  358 
Fronts,  hoot,  397 
Fryer,  Watt,  and   Holmes'9  tanning 

process,  209 
Fucus  crispus,  266 
Fuller's  earth,  297 
Fulling  stocks,  110 
Funcke's  tanning  process,  197 
FusanniB  compressus,  85 
Fustic  wood,  339 

GALL-NUTS,  43 
Galls,  21,  85 
Aleppo,  53 
blue,  73 
Chinese,  53 
decoction  of,  57,  58 
preen,  73 
infusion  of,  59 
Istrian,  53 
large  Mecca,  73 
nut,  73 
tamarisk,  86 
white,  73 

Gallic  tinctorum,  43 
Gallic  acid,  14,  18,  57 

preparation  of,  58 
Dumas'  method,  58 
Graham's  method,  58 
Liebig's  method,  58 
pharmaceutical  method,  59 
properties  of,  60 
Scheele's  method,  58 
fermentation,  (53 

prevention  of,  64 
Gallo-tannic  acid,  43 

tannin,  15 
Gambier,  or  terra  japonica,  53,  77,  85 

and  sumac  liquor,  377 
Gaub,  85 
Gaulard's  processes  of    tanning    by 

electricity,  255,  256 
Gelatine,  li,  91 

action  of  tannic  acid  on,  13 
bone,  452 
properties  of,  1 1 
sugar,  12 

Gelatinising  (glue -boiling),  450 
Gelatinous  tissue,  27 
Geranium  maculatum,  77,  85 


German  beam-knife,  236 
Getim  urbanum,  49 
Glace  goatskins,  327 

finishing,  341 

kid,  327 

leather,  310,318,323 
Glass  hydrometer,  91 
Glazed 'kid,  finishing,  311 
Glazing,  394 

box-calf,  356 

chrome  leather,  343 
Glecoma  hedcracea,  49 
Glossing  (glue-boiling),  440 
Glove-leather,  387 

chamois,  362 

Continental  method   of   prepar- 
ing, 313 

dyeing,  303 

hide,  386 
Gloves,  dog-skin,  435 

French  kid,  41 
Glue-boiling,  449 

carpenter's,  456 

fish,  446 

French,  452 

parchment,  453 

pieces,  treatment  of,  449 

waste,  452 

Glucose  in  leather,  459 
Gmelin  on  the  action  of  tannic  acid 

on  gelatine,  13 
Goat-skins,  40,  327,  328 

glace,  327-344 

dyeing  fancy  shades,  3M 

one-  and  two-  bath  methods  lor, 
326,  327 

Patna,  328,  419 

Swiss,  40 

Goldbeaters'  skin,  444 
Graham's  method  of  preparing  gallic 

acid,  58 
Grain  leather,  386 

splits,  288 
Graining,  382 

after  whitening,  382 

board,  hand,  382 
Grape  sugar,  458 
Green  dye,  300 

galls,  73 

hides,  29 

splitting,  411 

luminere,  304 

oak,  85 

sheepskins,  242 

vitriol,  261,  305 
Greening,  tannin,  iron,  13 
Grinding  the  bark,  237 


470 


INDEX. 


Grounding,  318 

Guest  and  Court's  process,  456 

Guiot's    process   of    quiclc    tanning, 

221 

Gum  arable,  340,  439 
Gut-dressing,  441 

strings  for  musical  instruments, 
446 


HAIR- WASTE,  457 
Hamer's  tanning  process,  197 
Hammer's  method  of  estimating  tan- 
nin, 93 

Hand-graining  board.  382 
press,  433 
reel,  235 
roller,  166 
Handler  liquor,  147 
the  rocker,  243 
Handlers,  147 
Handling,  148,  242 
Hard   leather,   tanning   process   for, 

181 

Harness   and    upper  leather,  manu- 
facture of,  223 
leather,  223 
Harvesting  bark,  72 
Hazel  bark,  54 
Heinzerlmg's  chrome  processes,  262, 

263,  324 

Hemlock,  54,  85 
extract,  77 

lime  rough  leather,  272 
sweat  sole  leather,  272 
tannage,  389 
tanning,  245 

Hibberd's  process  of,  252 
of  New  Lebanon,  N.J.,  249 
llemolin  and  logwood,  dyeing  with, 

337 

Hempseed,  218 
Herb  bennet,  17 
Herse,  437 
Hewitt  on  •  Lowenthal's    method  of 

estimating  tannin,  97 
Hibberd's  process  of  hemlock  tan- 
ning, 252 

Hide  and  skin  cuttings,  456 
glove,  386 
hook,  119 
ox,  28 

splitting  machine,  328,  375 
Hides,  28,  29 

and  skins,  27 

depilation  of,  115 
condition  of,  28 


Hides,  ass  and  mule,  38 
brined,  37 
buffalo,  37 

cold  sweating  of,  229 
cow,  226 

split,  for  brown  bags,  396 
dried,  30,  110 

Brain's  process  for  soften- 
ing, 111 
salted,  31 
softening,  110 
dry,  salted,  112 
Hint,  30,  110 
green  or  fresh,  treatment  of,  108 

splitting,  411 
hippopotamus,  38 
horse,  38 

tawed.  38 
imported.  109 
infected,  271 
method  of  salting,  109 
native,  30 
ox,  38 

raw,  cleansing,  109 
condition  of,  108 
stocking,  400 
salted,  30 
Schult/'s  views  on  the  treatment 

of,  112 

selection  of,  223 
treatment  of,  after  sweating,  231 

of,  in  sweat  pits,  2uO 
walrus,  38 
weight  of,  30 
wet  salted,  112 
High  shoes,  black  grain,  396 
llinan,  85 

Hippopotamus  hides,  38 
Hog  and  pig  skins,  41 
plum,  85 
skins,  41 
Holm-tree,  85 
Honeysuckle,  85 
Hops,  218 
Horse,  the,  104 
bot,  33 

chestnut  bark,  40 
hair,  446 
hides,  38 

tawing,  38 
Housings,  39 
Huldi,  85 
Human  skin,  24 
Hungarian  larch  extract,  77 
Hungary  leather,  290 
Hydrate  of  lime,  117 
Hydraulic  press,  377,  453 


INDEX. 


Hydrochloric  ncid,  45,  95,  325 

chrome  oxide,  319 
Hydrogen,  sulphuretted,  46 
Hydrometer,  89 

glass,  91 
Hydrostatic    pressure,    tanning    by, 

206 
Hygrometer,  158 

Mason's,  158 
Hyposulphite  of  soda,  324 


TLLUSTRATION  of  the  skin,  86 
J-     Imitation  chamois  leather,  40 

kid,  312 
Imitation  Morocco  leather,  287 

pigskin,  414 
Imported  hides,  119 
Indian  catechu,  75 
Indigo  blue,  95 

carmine,  97 
Induliue,  304 

Inflation  (gut  dressing),  4-13 
Influence  of  light  on  leather,  161 
Infusion  of  galls,  96 

oak-bark,  96 

sumach,  96     * 

Instruments,  musical,  gut  strings  for, 
446 

stringed,  447 
Intestines,  cleansing,  447 

sheep,  cords  from,  445 

treatment  of,  447 
Iris  pseudacorus,  49 
Irish,  old,  process  of  tanning,  208 
Iron,  acetate  of,  281 

bark,  85 

basic  sulphate  of,  261 

blueing  acids,  14 
tannin,  13 

oxide  salt,  261 

persalts  of,  13 

persulphate  of,  13 

protosulphate  of,  51 

sesqnichloridc  of,  52 

sesquioxide  of,  264 

soap,  2(51 

sulphate  of,  264 

tannate  of,  51 
Isinglass,  11 
Istrian  nut  galls,  33 


JAMAICA  kino,  75 
*J     Japan  earth,  77 

leather,  298 
Jennings'  tanning  process,  174 


KAOLIN,  100 
Kararalli,  85 

Knrtstoff's  description  of  Russia  lea- 
ther manufacture,  277 
Kassu,  85 

Keasley's  tanning  process,  182 
Kermes  oak,  85 

bark,  53 

Kettledrums,  439 
Kid  butt-setting  machine,  380 
calf,  for  uppers,  314 
glazed,  finishing,  341 
imitation,  312 
leather,  307 

currying,  371 
dyeing,  300 
French,  300 
skins,  40 

treatment  of,  307 
Kino,  or  gum  kino,  49,  76,  85 
Amboyna,  75 
Columbian,  76 
Jamaica,  75 
Kip-skins,  113 

butts,  currying,  373 
offal,  386  " 
Kips,  28,  37,  361,  373 

East  India,  37,  392 
Kleman's  tanning  process,  204 
Knapp's  process  of  chemical  tanning, 

261 

chrome  process,  324 
Knife,  beam,  French.  236 
curriers'  317,  370 
fleshing,  125 
moon,  318 
rounding,  127 
shaving,  371 
unhairing,  124 
Knoppern,  85 

Knowlys  and  Duesbury's  tanning  pro- 
cess," 208 
Kohlrausch's  process    for   preparing 

tannic  acid,  48 
Krameria  triandria,  79,  86 
Krameric  acid,  80 
Krupelboom,  85 
Kullaballi,  85 

T  AMBS'  skins,  39 

-L^     Lamium  album,  49 

Lampblack,  383,  395 

Lange,  on  the  abusive  treatment  of 

hides,  35 
Larch,  85 
•  bark,  54 
extract,  77 


472 


I.VDEX. 


Large  Mecca  galls,  73 
Larix  americana,  85 

europaea,  85 
Lathe  cords,  444 
Lauras  sassafras,  80 
Laver  liquor,  71 
Layers,  the,  149,  243 
Laying  the  grain,  155 
Leaches,  146 
Leaching,  238 
Lead,  carbonate  of,  45 
Leather,  American  trade  in,  372 
belt,  38 
bleaching,  269 
buff,  38,  363 

process,  303 

chamois,  39,  357,  361,  363 
colouring,  362 
glove,  362 

manufacture,  357-363 
chrome,  manufacture,  323-347 

Schultz's  patent,  324 
cloth,  American,  267 
Cordovan,  2,  288 
crop  or  belt,  226 
currying  kip,  371 
dressing,  410 

machinery,  410-412 
dyeing,  299 
embossed,  7 
embossing,  431 
enamelled,  297 
extinction  of  wax,  372 
feeding  of,  20,  214 
French  kid,  310 
glace,  310 
glove,  387 

Continental  method  of  pre- 
paring, 313 
dyeing,  303 
glucose  in,  459 
goat-skin,  327 
grain.  382,  386 

hard,  tanning  process  for,  181 
hemlock  tanned,  245 
sweat  sole,  272 
Hungary,  290 
imitation  chamois,  40 

Morocco,  287 

influence  of  light  upon,  161 
Jamaica,  298 
Japan,  298 
kid,  307 

dyeing,  300 
Levant,  392 
machine-buffed,  390 
Madras,  374 


Leather,  manufacture  of  harness  and 

upper,  223 

manufacture,     machinery     em- 
ployed in,  399-430 
Morocco,  2,  282 
dyeing,  299 
oak  lime,  272 
oiled,  394,  435 
ornamental,  42 
ornamenting,  431 
patent,  297 
preservative,  328 
red  Morocco,  299 
rolling,  165 
rough,  hemlock  lime,  272 

oak  lime,  272 
Russia,  276 

another  method  of  prepar- 
ing, 279 
black,  281 

manufacture,  Count  Kart- 
stoff's  description  of, 
277 

shagrin,  2,  38 
shammy,  or  shamoy,  39 
sheep,  white,  318 
skiver,  288,  322,  356 
smoke-cured,  5 
soaking  the,  374 
soft,  tanning  process  for,   181, 

374 

softening  the,  374 
tanning  butts  for  sole,  143 
tawed,  317 
to     determine     when      tanned 

throughout,  167 
union  lime  sole,  272 
vegetable,  265 
vitriol-raised,  241 
Wallachia,  291 
wax,  372,  396 
waxed,  372,  374,  383 
white,  manufacture  of,  306 
Yufts,  or  Russia,  281 
Leather-making    revolutionized     by 

chrome  power,  323,  400 
Leathers,  currying  various,  395 
light,  manufacture  of,  276 
Leaven,  294 
Lecythis  ollaria,  85 
Leicester  sheepskins,  435 

willow,  21 
Leucine,  12 

Leucospermum  conccarpuin,  85 
Ley,  ash,  276 
Leys,  potash,  447 
Liber,  69 


INDEX. 


473 


Licbig's  method  of  preparing  gnllic 

acid,  58 

Light  leathers,  manufacture  of,  276 
Lignin,  72 
Lignum  vite,  369 
Lime,  acetate  of,  308 

arsenic,  329,  330 

carbonate  of,  117 

caustic,  115 

cream  of,  43G 

depilationby,  115,  329,  330 

Dr.  Davy  on  the  action  of,  on 
animal  matter,  121 

hydrate  of,  117 

middle,  315 

milk  of,  115,  449 

process,  115 

supposed  disadvantages  of, 

properties  of,  117 

8*ccharate  of,  141 

storing  the,  118 

sulphuret  of,  132 

tannate  of,  16,  71 

waste,  458 
Lime-water,  45 
Limestone,  117 
Liming,  118,  224,  307,  329 

and  soaking,  315 

Continental  method  of,  120 
Lincoln  sheepskins,  435 
Linseed  oil,  265 
Liquor,  bran,  296 

logwood,  385 

oak -bark,  269 

List,  of  tanning  materials,  84 
Lithrum  salicaria,  49 
Live  vat,  120 
Loft  or  shed,  drying,  157 
Logwood  and  hemolin,  dyeing  with, 

327 

Lomas'  tanning  process,  176 
Lombardy  poplar,  54 
Lowenthal's    method    of    estinv  ting 
tannin,  94 

Hewitt  on,  97 
Procter  on,  100 
Lumiere  green,  304 
Lupkin's  unhairing  process,  233 

MACHINE,  bark  mills,  404 
blocking,  397 
buffing,  417 
buff  leather,  390 
butt-stretching,  425 
depilating  and  fleshing,  402,  421 
disintegrating,  405 


Machine,  embossing,  414,  431-433 
Huxham  &  Brown's,  431, 
the  Altura,  431 
fleshing,  315 
fluffing,  426 
glazing,  427 
kip  butt-setting,  380 
measuring,  429,  430 

Connolly's  areameter,  430 
printing,  433 
rolling,  166,  409 
scouring,  155,  413 
scudding,  422 
setting,  414 
shaving,  375,  410 
softening,  416 
splitting,  320,  375,  411 
staking,  425,  426 
stocking,  400 
striking,  164,  406 
Mulling,  415 
unhairing  and  fleshing,  419 

Duplex,  315 

Machinery  employed  in  leather  manu- 
facture, 399-430 

embossing,  414,  431-433 
sole  leather  tanning,  400-419 
unhairing  and  fleshing  by,  315 
used  in  chrome  leather  manu- 
facture, 415,  419-430 
Madder,  219 
Madras  leather,  374 
Magnesia,  chromnte  of  262 

tannate  of,  71 
Mala  insana,  73 
Malabar  catechu,  75 
Malic  acid,  65 
Manganese,  oxide  of,  264 

sulphate  of,  264 
Mangrove,  85 
Manufacture  of  box-calf,  348-356 

of  chamois,  or  oil-leather,  357- 

363 
of  chrome  leather,  323-347 

machinery,  415,  419-430 
of   harness  and  upper   leather, 

223 
of  leather,  machinery  emploved 

in,  397 

of  light  leather,  276 
of  white  leather,  306 
Marsh  rosemary,  85,  86 
Mason's  hygrometer,  158 
Materials,  drum-stuffing,  378,  380 
Measures  and  weights  of  the  metrical 
sj'stem,  460 

of  capacity,  461 


474 


INDEX. 


Measures,  of  length,  461 

French  metrical  or  decimal, 

460 
volume,  French  metrical  or 

decimal,  460 

Measuring  (gut  dressing),  443 
Memel,  calf -skins  for,  395 

roller,  395 
Mene,  M.,  269 
Merat-Gmllot's  process  for  preparing 

tannic  acid,  45 

Meriten's  process  of  tanning  by  elec- 
tricity, 258 
Meta-gallic  acid,  60 
Methanil  yellow,  302 
Method  of  preparing  Russia  leather, 
279 

Bell  Stephens',  for   estimating 

tannin,  92 

Continental,  of  preparing  cattle 
intestines,  441 

of  preparing  glove-leather, 

313 

Davy's,  for  estimating  tannin,  92 
Hammer's,  for  estimating  tan- 
nin, 93 
Indian,  of  preparing  elk-skins, 

268 

Lowenthal's,  for  estimating  tan- 
nin, 94 

of  drying  the  tanned  butts,  Ame- 
rican, 156 

of  estimating  tannin,  Hewitt  on 
Lowenthal's,  97 
Procter  on  Lowcnlhal'c,  100 
Kampacker's,  102 
of  liming,  Continental,  120 
of  salting  hides,  109 
single  pit,  118 
Methods  of  tanning,  old,  144 

in  up-to-date  leather  works,  372 
Methyl  violet,  304 

Metrical    or    decimal    measures    of 
length,  French,  460 

of  volume,  French,  460 
Michel,  Kollen,  and   Hortzog's  pro- 
cess, 176 
Middle  lime,  315 
Milk  of  lime,  115,  449 
Milling,  359,  364,  366 
Mimosa,  85 

bark,  54,  83 

Miscellaneous  processes,  268 
Mixed  tannages,  151 

vitriol,  305 

Mixture  stuffing,  379,  380 
Mochrus,  85 


Modern  system  of  tanning,  145 
Mogadore  skins,  40 
Molina  sumach,  79 
Molle,  85 

Moon-knife,  318,  342 
Mora,  85 

excelsa,  85 
Mordants,  301,  337 

corichrome,  346 
Morfit's  observations  on  tsnnin,  55 

remarks      on    white     dressing, 

295 

Moriuga  pterygosperma,  86 
Morocco  leather,  2,  282 

dyeing,  299 

imitation,  38,  287,  414,  432 

red,  299 
Mould,  156 
Mouren's  tanning  process  by  pressure, 

209 
Mr.  Ashe's  description  of  the  skin, 

24 

Mucilage,  439 
Muriate  of  tin,  191 
Murici,  85 
Musical  instruments,  gut  strings  for, 

446 

Mutton  tallow,  440 
Myrobalans,  54,  81,  85,  392,  405 
Myrtle,  85 


NAHRUNG,  313 
Naphthaline,  263 
yellow,  302 
Naphthol  yellow,  304 
Native  hides,  30 
Neb  neb,  85 
Nectandra,  86 
Needham's  process  of  quick  tanning, 

218 
Nets,    sails    and    cordage,    tanning, 

265 

New  tanning  materials,  86 
Newton's  tanning  process,  170 
Nigrosine,  304 
Nitrate  of  soda,  262 
Nitric  acid,  55,  261 
Noesiter's  tanning  process,  198 
Nuessly's  process  of  quick  tanning, 

218 
Nut-galls,  15,  73 

Aleppo,  53 
Chinese,  53 
Istrian,  53 
Nutmeg,  444 
Nymphtea  alb.i,  49 


IXDEX. 


475 


OAK,  85 
bark,  21,  69,  143 

infusion,  98,  278 
tanning  with  decoction  of, 
265 

coppice,  70 

English,  70 

kcrmes,  53 

lime  leather,  272 

rough  leather,  272 

trmncd  basils,  435 

valonia,  81,  405 
Oakwood  extract,  77,  377 
Oatmeal,  278 
Observations  on  the  origin  of  warbles, 

32 

CKstrus  bo  vis,  31,  34 
Offal,  30 

kip,  38(5 
Oil,  almond,  311 

birch-tar,  2G5 

cod-liver,  378,  383 

cod,  383,  384 

drying,  297 

fish,  311 

leather,  357 

linseed,  394 

neatsfoot,  337,  340 

of  birch,  281 

of  sesame,  289 

of  vitriol,  241 

rape,  265 

Russian,  281 

sod,  360,  379 

tanning,  357 

thyme,  263 
Oiled  leather,  394,  435 

buff  leather,  435 

chrome  leather,  340 
Old  Irish  process  of  tanning,  2G3 

methods  of  tanning,  144 

oak  bark,  53 
Olea  europaea,  85 
Olive,  85 

dye,  300 

On  the  co:?t  of  tanning,  272 
One-bath  method  for  calf-skins,  348 
for  goat-skins,  326 
Ooze,  21,  146 

preparation  of,  146 
Operation,  tawinsr,  306 

shaving,  375 
Orach,  wild,  3 

Orgereau's  tanning  process,  173 
Ornamental  leather,  42,  431 
Ornamenting  leather,  431 
Ovipositor,  32 


Oxalic  acid,  101,  301 
Ox-bot,  33 

gadfly,  33 
Oxide  of  calcium,  117 

of  iron,  salt  of,  261 

of  manganese,  264 

PAGE'S  tanning  process,  191 
Palachy,  85 

Palmer's  process  of  dcpilation,  134 

Paper-mnking,  pulp  for,  from  waste 
tan,  455 

Papyrus,  437 

Paraffin,  265 

Parchment  glue,  453 

and  vellum,  preparation  of,  437 
vellum  and  shagreen,  437 

Parenchyma,  69 

ParneU's  views  on  tannic  acid,  50 

Paste,  tawing,  313 

Patent  leather,  297 

Patents  for  tanning,  first  English,  169 

Pates,  231 

Patna  goat-skins,  328,  419 

Pearlash,  American,  176 

Pectin,  72 

Pe'louze's  process  for  preparing  tannic 
acid,  43 

Pelt,  24 

Pelts,  rounding.  126 

Pendulum  roller,  American,  167 

Pteonia  officinalit*,  49 

Percentage  of  tannin  in  vegetable  sub- 
stances, table  of,  53 

Pergamena,  437 

Permanganate  of  potash,  94 

Perones,  Roman,  6 

Pcrsalts  of  iron,  13 

Persian  berries,  304 

Persulphate  of  iron,  13 

Peru  catechu,  53 

Pharmaceutical  methods  of  preparing 
gallic  acid,  59 

Phloxine,  302 

Phosphoric  acid,  301 

Photogen,  263 

Phylanthus  cmblica,  84 

Phyllocladus  asplenifolia,  84 
trichomanoides,  86 

Physiological  uses  of  bark  in  plants, 
69 

Pickled  skins  (Australian  and  New- 
Zealand),  327 

Pig  and  hog  skins,  41 

Pigskin,  imitation,  414 

Pinus  excelepeusis,  84 
pinea,  86 


476 


INDEX. 


Pits,  swent,  229 

treatment  of  hides  in,  230 
Plumbago  europaea,  84 
Plum-tree,  54 
Polishing  buffs,  38 
Polygonum  amphibium,  86 

bistorta,  49 
Pomegranate,  54,  85 
Popularity  of  chrome  process,  372 
Porpoise  skins,  42 
Porto  sumach,  79 
Potash,  bichromate  of,  2G6,  324 
bitartrate  of,  175 
carbonate  of,  46 
chromate  of,  263 
leys,  447 

permanganate  of,  94 
prussiate  of,  262 
tannate  of,  71 
Potassium,  chloride  of,  191 

tungstate  of,  264 
Potent!  lla  argentea,  49 

reptans.  43 

Poterium  sanguisorba,  49 
Pratt's  system  of  tanning,  245 
Preliminary  operations,  108 
Preparing  elk-skins,  Indian  method, 
268 

glove  1  eather,  Continental  m  ethod 

of,  313 

the  currier's  knife,  317,  370 
Preparation  of  cattle  intestines,  441 
of  gallic  acid  from  galls,  58 
parchment  and  vellum,  437 
size  for  currying,  383-385 
tannic  acid,  Badvil  and  Lien- 

ders'  process,  47 
tannic  acid,  Berzelius'  process, 

44 
tannic     acid,      Bouillon-Le- 

grange's  process.  45 
tauuic  acid,  MM.  Coez's  pro- 
cess, 47 
tannic  acid,  Deyeux's  process, 

46 
taunic    acid,    Dize^s   process, 

45 

taunic  acid,  Kohlrausch's  pro- 
cess, 48 
tannic    acid,    Merat-Guillot's 

process,  45 
tannic  acid,  Pe'louze's  process, 

43 
tannic  acid,  Proust's  process, 

46 

tannic   acid,   Schering's   pro- 
cess, 46 


Preparation    of     tannic     acid,    Ser- 

turner's  process,  46 
the  blacking  for  currying,  390 
the  ooze,  146 
"  Press  "  leach,  239 

hydraulic,  377,  453 
Priego  sumach,  79 
Priestman's  striker,  407 
Principles  of  tanning,  7 
Printing  machine,  433 
Process,    Badvil    and    Lienders,    for 

preparing  tannic  acid,  47 
Berzelius',  for  preparing  taunic 

acid,  44 

Bez  and  Sons',  for  tawing,  8,  192 
Bouillon-Legrange's,  for  prepar- 
ing tannic  acid,  45 
buff  leather,  363 
chrome,  Heinzerling's,  262,  263, 

324 

popularity  of,  372 
Knapp's,  324 
Schultz's,  324 
Coez's,  for  preparing  taunic  acid, 

47 

Crosse's,  of  tanning  by  electri- 
city, 258 
Deyeux's,  for  preparing  tannic 

acid,  46 
Dize's,  for  preparing  tannic  acid, 

4o 

Drake's  tanning,  8,  207 
electrotype,  431 
for      softening      dried      hides, 

Brain's,  111 

Gaulard's,  of  tinning  by  electri- 
city, 255,  256 
Guest  and  Court's,  456 
Hibberd's,  of  hemlock  tanning, 

Keasley's,  8,  182 
Knowlys'  and  Duesbury's,  8,  208 
Kohlraiisch's,  for  preparing  tan- 
nic acid,  48 
lime,  115 

supposed    disadvantages  of, 

121 
Merat-Guillot's,    for    preparing 

tannic  acid,  45 

Meriten's,  of  tanning  by  electri- 
city, 257 
Nossiter's,  8,  198 
of  bating,  Turnbull's,  141 
bating,  Warrington's,  141 
chemical    tanning,    Vander- 

straaten's,  266 
depilation,  Beck's,  136 


INDEX. 


477 


Process  of  depilatiou,  Palmer's,  134 
tanning,  Drake's,  207 

Frver,  Watt  and  Holmes's, 

'209 
Knowlys  and  Duesburv's, 

208 

Mouren's,  209 
Spilsbury's,  206 
Peloiue's,  for  preparing  tannic 

acid,  43 
Proust's,   for   preparing   tnnnic 

ncid,  4G 
quick  tanning,  211 

Baron's  process,  219 
Bell's  process,  219 
Danish  process,  221 
Dietz's  process,  217 
Guiot's  process,  221 
Ncedham's  process,  218 
Nuessly's  process,  218 
Schering's,  for  preparing  tannic 

acid,  46 
Serturuer's,  for  preparing  tnnnic 

acid,  46 

Spilsbury's,  8,  206 
tanning,  Aldnch's,  171 

Ballatschano  and   Trenk's, 

174 

Bez  and  Sons',  192 
Burbidge's,  203 
Cox's,  198 
De  Bock's,  196 
Desmond's,  202 
for  hard  leathers,  181 
for  soft  leathers,  181 
Funcke's,  197 
llamer's,  197 
Jennings',  174 
Keasley's,  182 
Kleman's,  204 

l.i  Mi;. 'is',    17(» 

Michel,  Kollen  and   Hert- 

zog's,  176 
Newton's,  170 
Nossiter's,  198 
Old  Irish,  268 
Orgereau's,  173 
Page's,  191 
Snyder's,  196 
unhniring,       Prof.       Lupkin's, 

233 
Ward's,  of  tanning  by  electricity, 

254 
Processes     of      chemical     tanning, 


Knapp's,  261 
[ein/erliugr's 


Hein/erliug's  chrome,  202,  263 
miscellaneous,  268 


Procter  on    Lowenthal's    method   of 

estimating  tannin,  100 
Properties  of  gallic  acid,  60 
of  gelatine,  11 
lime,  117 
tannic  acid,  49 
Prosopis  pallida,  84 
Protea  grandiflora,  86 
Protosulphate  of  iron,  51 
Proust's  process  ior  preparing  tannic 

acid,  46 

Pressure,  tanning  by,  206 
Prussian  blue,  297 
Prussiate  of  potash,  263 
Pterocarpus  eriuaceus,  76 

marsupium,  76,  85 
Puce  dyes,  300 
Pudis  sumach,  79 
Pulp  for  paper-making  from   waste 

tan,  455 

Punica  granatum,  85 
Pure  aniline  colours,  dyeing  with,  304 
or  drench,  140,  316 
tannic  acid,  51 
Purimbas,  85 
Puring,  316,  332 
Putrefactive  fermentation,  128 
Putrid  fermentation,  442 
Putting  out  chrome  leather,  340 
Pyenocama  macrophylla,  84 
Pyrogallic  acid,  14,  60,  61 
Pyroligneous  acid,  65,  67 

QUEBRACHO,  86 
extract,  77 

Quercitannic  acid,  101 
Quercitron,  86 
Quercus  coccifera,  70,  85 
aegilops,  81,  86 
falcata,  70 
glomerata,  70 
ilex,  85 

infectoria,  43,  74,  85 
macrolepis,  81 
pedunculata,  70,  85 
pubescens,  85 
robur,  70 
rubra,  70 
sessiliflora,  70,  85 
stenophylla,  81 
suber,  70,  84 
tinctoria,  70,  86 
Quick  tanning,  211 

Baron's  process,  219 
Bell's  process,  219 
Danish  process,  221 
Dietz's  process,  217 


478 


INDEX. 


Quick  tanning,   Dr.  lire's  views  on, 

213 
Dussauce's  observations  on. 

215 

Guiot's  process,  221 
Needham's  process,  218 
Nuessly's  process,  218 

TDAISING,  138,  292,  297 
-1  «•  or  swelling,  134 

Raifing  with  vitriol,  241 
Ramspacker's  method  of  estimating 

tannin,  102 
Bape  oil,  205 
Kaw  hides,  abusive  treatment  of,  35 

]VI.  Lange  on  the  abusive  treat- 
ment of,  35 
Reactions  of  tannic  acid,  52 

stocking,  400 
Recipes  for  size,  384,  385 
lied  arsenic,  329 

birch,  86 

dressing,  295 

dve,  299 

Morocco  leather,  299 
Remarks,  Mortit's,  on  white  dressing, 

295 

Reptile  skins,  431 
Hesin,  263,  379 
Re-tanning,  376,  392 
Rete  mucosum,  23 
Rliatany,  68,  86 

root,  53,  80 

Rheum  rhaponticum,  49 
Rlius  coriaria,  78,  86 

cotinus,  77 

myrtifolia,  85 

semialata,  74 
Roan,  290 
Roans,  435 
Roller,  American  pendulum,  167 

electrotyped  copper,  3o2 

hand,  165 
Rolling  machine,  166,  409 

the  leather,  165 
Roman  calcei  mullei,  6 

crepidd,  6 

perones,  6 

shoes,  6 

soleae,  6 

strings,  447 
Bosa  cauina,  49 

gallica,  49 
Bounding,  or  trimming,  236,  373 

and  sorting,  373 

knife,  127 

table,  126 


Rounding  the  pelts,  126 

Rubstone.  370 

Russia  leather,  black,  281 

leather,  2,  277 

method  of  preparing,  279 

or  Yufts,  279 

wormwood,  289 
Rye  meal,  294 

OACCHARATE  of  lime,  141 

^     Saffron,  86 

Sagre,  3 

Sagri,  3 

Sal  ammoniac,  440 

soda,  218 
Salix  alba,  86 

cinerea,  86 
Salt,  iron,  261 

solution,  191 
Salted  hides,  30 

dry,  112 

wet,  112 
Saltpetre,  191 
Salts,  ammoniacal,  255 

ferric,  14 

Salvia  officinalis,  49 
Salzburg  vitriol,  305 
Sam,  or  samm,  155,  396 
Sandstone,  369 
Sanguisorba  officinalis.  49 
Sassafras,  86 

bark,  54 
Saul  tree,  86 
Saxon  blue,  300 
Scarf  skin,  11,  23,  26 
Scheele's  method  of  preparing  gallic 

acid,  58 
Schultx  on  the  cost  of  tanning,  272 

description   of  the  turret  drier 

by, 159 
Schultz's*  chrome  leather  process,  324 

views  on  the  treatment  of  hides, 

112 

Scilla  maritima,  86 
Scotch  stone,  370 
Scouring,  155 

(gut  dressing),  441 

house,  368 

machines,  155,  413 

stone,  155 
Scraping,  442 
Scud,  316 
Scudding,  125,  140,  284,  316,  333,  3G5, 

366 
Seal  skin,  297 

skins,  41 
Seaside  grape,  86 


INDEX. 


479 


Seasoning,  317,  343,  355,  394 
{Seasons  i'or  lox-calf,  355 

for    chrome   leather,  3-12,    343, 

346 

Sebaceous  glands,  26 
Second  boiling  (glue),  452 
Seguiu's  theory  of  the  art  of  tanning, 

Sir  II.  Davy  on,  17 
Dr.  Ure  on,"  16 
Duss^iuce  on,  16 
Selection  of  hides,  31,  223 
Sensitive  plant,  83 
Serpent  and  crocodile  skins,  42 
Sen  timer's  process  for  preparing  tan- 

nic  acid,  46 
Service  tree,  55 
Scsnme,  oil  of,  289 
Setting,  380 

kip  butt,  machine,  380 
Sesquichloride  of  iron,  52 
Sesquioxide  of  iron,  264 
Shagreen,  440 

fish,  440 

leather,  2,  38 

parchment  and  vellum,  437 
Shamois  leather,  39 
Shark  skin,  440 
Shaver  or  beamsman,  375 
Shaving,  317,  336,  351 

by  machinery,  375,  410 

knife,  371,  410 

operation,  375 
She  oak,  86 
Sheep  intestines,  cords  from,  445 

leather,  white,  318 

akius,  39 

classification  of,  435 
green,  242 
splitting,  320,  392 
tawing,  318 
Shoe.*,  high,  black  grain,  396 

Roman,  6 

Shop,  the  currying,  369 
Shorea  robusta,  86 
Sicilian  sumach,  78 
Silicon,  sulphate  of,  266 
Single  pit  method,  118 
Sir  John  Lubbock  on  the   origin  of 

warbles,  32 
Sirnabelli,  86 
Size,  recipe  for,  384,  385 

preparation  of,  384,  453 

for  waxed  leather,  385 
Sizes,  bottom,  383,  384 
Skeleton  drum.  235 

reel,  235 


Skin,  23,  26 

and  hide  cutting?,  456 

bottles,  5 

buck,  dressing,  366 

camel,  440 

composition  of,  27 

deer,  41 

fish,  or  fish  shagreen,  440 

goldbeaters',  441 

hog,  41 

horse,  440 

human,  24 

illustration  of  the,  26 

Mr.  Ashe's  description    of  the, 

24 

seal,  298 
shark,  440 

structure  of  the,  23,  36 
wild  ass,  440 
Skins    28 

alligator,  42,  431 

<tc.,  electrotyped,  432 
and  hides,  28 

condition  of,  38 
depilation  or  unhairing 

of,  115 
asses',  439 
boa-constrictor,  432 
calf,  for  memel,  395 
tawing,  314,  435 
calves',  38 

chamois,  colouring,  362 
crocodile,  432 

elk,  Indian  method  of  prepar- 
ing, 268 

for  drumheads,  439 
goat,  40,  327,  328,  419 
hog  and  pig,  41 
kid,  40 

treatment  of,  307 
lamb,  Cape,  435 
lambs',  435 
Mogadore,  40 
pickled   (Australian    and    New 

Zealand),  327 
porpoise,  42 
reptile,  431 
seal,  41 

serpent  and  crocodile,  42 
sheep,  39 

Cape,  435 

Cotswold,  435 

classification  of,  435 

Leicester,  435 

Lincoln,  435 

Southdown,  435 
smoking,  279 


48o 


INDEX-. 


Skins,  split,  440 

splitting,  320,  380,  411 

tawing,  306 

treatment  of,  435 

Welsh,  435 
Skiver,  39,  288,  325 

leather,  322,  356 
Sleaker,  377,  381,  393 

stone,  387 

whitening,  381,  390 
Slimed,  312 
Small  steel,  370 
Smoke-cured  leather,  5 

house,  128 
Smoking  skins,  279 
Snyder's  tanning  process,  196 
Soaking  and  liming,  315 

the  leather,  374 
Soap,  brown,  391 

iron,  261 

soft,  352 
Sod  oil,  360,  379 
Soda  ash,  234 

caustic,  131 

chromate  of,  262 

hyposulphite  of,  324 

nitrate  of,  262 

sal,  218 

thiosulphite  of,  324 
Sodium,  sulphide  of,  133 

tungstate  of,  264 
Soft    leather,    tanning    process    for, 

181 

Softening  dried  hides,  110 
Sogah,  86 
Solese,  Roman,  6 
Sole  butts,  456 

leather  tanning,  machinery  used 

in, 400-430 

Soluble  chromates,  263 
Sorting  and  rounding,  373 
Sources  of  tannin,  68 
Southdown  sheepskins,  435 
Spanish  chestnut,  21 

white,  180 
Spent  tan,  455 

Spilsbury's  tanning  process,  206 
Split  cow-hides,  currying,  39G 
for  brown  bags,  396 

flesh,  289 

sheepskins,  440 
Splitting,  39,  387,  388 

machine,  320,  375 

sheepskins,  320 
Spondias  lutea,  85 
Squill,  53 
Squills,  86 


Stake,  320 

Staking,  310,  317,  320,  341 

Starching,  382 

Statice,  53,  86 

coriaria,  85,  86 
Steam  sweat,  229 
Stearic  acid,  312 
Stearine,  263,  312,  379 
Steep,  bran,  318 
Still-born  calves,  437 
Stocking,  859,  366 
Stocks,  fullinar,  110 
Stockstone,  377 
Stone  pine,  86 

sleaker,  387 
Stoning,  382,  387 
Storing  the  lime,  118 
Straight-grain  roller,  396 
Strasburg  vellum,  439 
Striker,  Priestman's.  407 
Striking,  163,  308 

a  butt,  164 

machine,  164 

pin,  163 
Striking  out  chrome  leather,  336,  340, 

351 

Stringed  instruments,  446 
Strings,  Roman,  447 
Structure  of  the  skin,  23,  26 
Stryphnodendron  barbatemas,  86 
Stuffing      machine      mixture,      379, 

380 

Subaujuna,  86 
Sugar,  gelatine,  12 

grape,  459 
Sulfamine  dyes,  345 
Sulphate  of  alumina,  170 
copper,  264 
iron,  basic,  261 
manganese,  264 
protoxide  of  iron,  264 
silicon,  266 
zinc,  221,  264 
Sulphide  of  sodium,  depilation  bv,  133, 

330 
Sulphur,  234 

chloride  of,  265 
Sulphuration,  443 
Sulphuret  of  lime,  132 
Sulphuretted  hydrogen,  46,  329 
Sulphuric  acid,  95,  141,  174,  301,  337, 

388 
Sumach,  86 

and  gambier  liquor,  377 

bath,  388 

Alcamo,  78 

Donzeri,  79 


INDEX. 


481 


Sumach,  infusion,  97 

Molina,  79 

Porto,  79 

Portuguese,  79 

Priego,  78 

Silician,  78 

tanning,  285 

Valladolid,  79 

Supposed  disadvantages  of  the  lime 
--  process,  121 
Suspenders,  153 
Suspension,  tanning  b}',  153 
Sweat  pits,  229 

treatment  of  hides  in,  230 

steam,  229 
Sweating,  128 

cold,  129,  229 

depilation  by,  128 

of  hides,  cold,  229 

treatment  of  hides,  after,  231 
Sweet  liquors,  251 

oil  of  almonds,  311 
Swelling,  or  raising,  138 
Swiss  goat-skins,  40 
Sycamore  bark,  54 

System,  metrical,  weights  and  mea- 
sures of  the,  461 

modern,  of  tanning,  145 

TABLE  of  the  percentage  of  tannin 
in  vegetable  substances,  53 
Tallow,  buck,  396 
deer,  396 
mutton,  440 
Tallowing,  395 
Tamaria  gallica,  87 
Tamarisk  galls,  86 
Tamarix  indica,  86 
Tarn  pi  co  skins,  40 
Tan  pits,  152 
shrub,  55 
spent,  454 

Tan-burning  boiler,  454 
Tangede,  86 
Tannago,  French,  382 

hemlock,  389 
Tannate  of  iron,  51 

lime,  16,  71 
magnesia,  71 
potash,  71 
tin,  46 

Tanned  butts,  drying,  156 
Tanners'  machinery,  399-430 

waste,  utilisation  of,  455 
Tannicacid,  11,  43,  50,  301 

preparation  of,  Badvil  and 
LiemUrs'  process,  47 


2i 


Tannic  acid,  preparation  of,  Berzelius' 

process,  44 
preparation  of,  Bouillon-Le- 

grange's  process,  45 
preparation  of,  Coez's  pro- 
cess, 47 
preparation    of,    Deyeux's 

process,  46 

preparation  of,  Dize"s  pro- 
cess, 45 
preparation  of,Kohlrausch's 

process,  48 
preparation  of,  Merat-Guil- 

lot's  process,  45 
preparation    of,    Pelouze's 

process,  43 

preparation  of,  Proust's  pro- 
cess, 46 
preparation    of,   Schering's 

process,  46 
preparation   of,  Sertumer's 

process,  46 
properties  of,  49 
pure,  51 
reactions  of,  52 
Tannin,  11,  18,  43 

Bell  Stephens'  method  of  esti- 
mating, 92 

Davy's  method  of  estimating,  92 
Hammer's  method  of  estimating, 

93 
Hewitt  on  Lowenthal's  method 

of  estimating,  97 
Lowenthal's    method    of    esti- 
mating, 94 
Procter  on  Lowenthal's  method 

of  estimating,  100 
Ramspacker's  method  of   esti- 
mating, 102 

table  of  percentage  of,  in  vege- 
table substances,  53 
Tanning,  226 

American,  228 

as  distinguished  from  tawing, 

306 

bark,  143 
butts,  143 

for  sole  leather,  143 
by  electricity,  254 

Crosse's  process,  258 
Gaulard's  process,  255,  256 
Meriten's  process,  257 
Ward's  process,  254 
by  pressure,  206 

Drake's  process,  207 
Fryer,  Watt,  and  Holmes's 
process,  209 


482 


INDEX. 


Tanning,  by  pressure,  Knowlys  and 
Duesbury's  process,  208 

Mouren's  process,  209 

Spilsbury's  process,  206 
by  suspension,  153 
chemical,  Knapp's  process,  261 
Vanderstraaten's  process,  266 
chrome,  334,  349 
composition  for,  253 
cost  of  American,  272 
extracts,  74 

first  English  patents  for,  169 
glycerine  in,  269 
Heinzerling's    chrome    process, 

262,  324 
hemlock,  245 

Hibberd's  process,  252 

of  New  Lebanon,  N.  J.,  249 
materials,  68 
modern  system  of,  145 
nets,  sails,  and  cordage,  269 
old  Irish  process  of,  268 

methods  of,  144 
Pratt's  system  of,  245 
principles  of,  7 
process,  Aldrich's,  171 

Ballatschano  and  Trenk's, 
174 

Bez  and  Sons',  192 

Burbidge's,  203 

Cox's,  198 

De  Bock's,  196 

Dennis's  taolin,  349 

Desmond's,  202 

Funcke's,  197 

Guiot's,  221 

Hamer's,  197 

hard  leather,  181 

Jennings',  174 

Keasley's,  182 

Kleman's,  204 

Lomas',  176 

Michel,  Kollen,  and  Hert- 
zog's,  176 

Newton's,  170 

Nossiter's,  198 

Orgereau's,  173 

Page's,  191 

Prenzlau's  corin,  350 

Procter's,  350 

Snyder's,  19t> 

soft  leather,  181,  374 
processes,  169 
quick,  211 

Baron's  process,  219 

Bell's  process,  219 

Danish  process,  221 


Tanning,     quick,     Dietz's     process, 

217 

Dr.  Ore's  views  on,  213 
Dussauce's  observations  on, 

215 

Guiot's  process,  221 
Needham's  process,  218 
Nuessly's  process,  218 

Schultz  on  the  cost  of,  272 

Seguin's  theory  of,  15 

sole  leather,  machinery  used  in, 
400 

sumach,  285 

theory  of,  1 1 
Tanno-gelatine,  51,  91 
Tannometer,  102 
Tanolin,  349 
Taps,  or  leaches,  146 
Tarsekeha,  86 
Tartar,  299 
Tartaric  acid,  65,  301 
Tasmanian  laurel,  86 
Tawed  hides,  38 

leather,  317 
Tawing,  306,  314,  435 

as  distinguished  from  tanning. 
306 

calf-skins,  314 

operations,  306 

paste,  313 

Schultze's  process,  324 

sheepskins,  318 
Tea,  17 

Tennis  bats,  &c.,  cords  for,  446 
Terce,  86 
Terminalia  bellerica,  81 

chelula,  81,  85 

citrina,  85 

formentosa,  87 
Terra  japonica,  53,  86 
Thiosulphite  of  soda,  324 
Third  boiling  (glue),  452 
Thyme  oil,  3 
Tilia  Europaea,  49 
Tin,  chloride  of,  46 

muriate  of,  191 

tannate  of,  46 
Titration,  94 
To  determine  when  leather  is  tanned 

throughout,  167 
Tongs,  283 
Top-sizing,  384 
Tooth-board,  396 
Tormentil,  54,  86 
Tormentilla  erecta,  49 
Tormentilia  potentilla,  86 
Towhai,  86 


INDEX. 


483 


Trade  in  American  leather,  372 

Tramping  drum,  262 

Treatment  of  glue  pieces,  449 

green  or  fresh  hides,  108 
hides  after  sweating,  231 
hides  in  sweat  pits,  230 
intestines,  447 
kid  skins,  307 
skins,  435 

preliminary,  108 
with  alum  and  salt,  308 

Trees,  barking  of,  71 

Trichinae,  32 

Trichinosis,  32 

Trimming,  or  rounding,  23G,  342,  373 

True  skin,  11,  26 

Tucking,  362 

Tuga  vesca,  86 

Tumbler,  308,  415 
air-heated,  378 

Tungstate  of  potassium,  264 
of  sodium,  264 

Turnbull's  process  of  bating,  141 

Turning  over  (gut  dressing),  442 

Turpentine,  essence  of,  181 

Turret  drier,  American,  159 
working  of,  160 

Turwar,  86 

Two-bath  method  for  calf-skins,  348 
for  goat-skins,  327 


UNCARIA  GAMBIR,  74,  77,  86 
Unbairing,  124,  315 
Unhairing  and  fleshing,  315,  329 

by  machinery,  315,  402,  429 
by  Prof.  Lupkin's  process,  233 
knife,  124 
or  depilation  of  skins  and  hides, 

115 
Union  lime  sole  leather,  272 

splitting  machine,  322,  412 
Uppers,  calf  kid  for,  314 
Ure  on  Seguin's  theory,  16 
Utilisation  of  tanners'  waste,  455 
Uva  ursi,  49 


•\7ALLADOLID  sumach,  79 
'      Valonia,  54,  81,  86,  405 
Valonia  oak,  81 
Vanderstraaten's  process  of  chemical 

tanning,  266 

Various  leathers,  currying,  395 
Varnish,  297 

amber,  298 
copal,  298 


Vegetable  black,  297 

extractive,  45,  215 

tannin,  266 

wax,  265 

Vellum  and  parchment,   preparation 
of,  437 

parchment,  nnd  shagreen,  437 

Strasburg,  439 
Verdigris  cry  stall  ised,  439 
Vinegar,  292 

wood,  2181 
Violet  dye,  300 " 

n>  ethyl,  304 
Vitriol,  copper,  305 

green,  261,  305 

oil  of,  241 

raised  leather,  241 

raising  with,  241 

Salzburg,  305 

zinc,  305 
Vitriols,  mixed,  305 


TIT  A  GEN  boom,  86 
W      Wallachia  leather,  291 
Wai  run  hides,  38 
Warble  marks,  31 

Warbles,  observation  on  the  origin 
of,  32 

Sir  John  Lubbock  on  the  origin 

of,  32 

Ward's   process  of  tanning  by  elec- 
tricity, 254 

Warrington's  process  of  bating,  141 
Washing  and  cleansing,  224,  334,  360, 
365 

(gut  dressing),  442 
Waste,  glue,  453 

hair,  457 

lime,  132,  458 

tanners',  utilisation  of,  455 
Water  plantain,  86 

stove,  136 
Wax  leather,  372,  374,  396 

extinction  of,  372 

vegetable,  205 
Waxed  leather,  383 

kip  butts,  373 
Waxing,  383 
Weights  of  hides,  30 

and   measures  of   the  metrical 

system,  461 

Weinmannia  racemosa,  86 
Welsh  sheepskins,  435 

stone,  370 

Wet  salted  hides,  112 
Whip  cords,  4-16 


484 


INDEX. 


White  dressing,  130 

Morfit's  remarks  on,  295 

galls,  73 

leather,  manufacture  of,  306 

mangrove,  85 

sheep  leather,  318 
Whitening,  381,  382 

graining  in  after,  382 

sleaker,  381,  390 
Wild  ass  skin,  440 

orach,  3 
Willow,  86 

bark,  54 

Leicester,  21 
Wilson's  striker,  407 
Winter's  barl*,  55 
Woo-pei-tzee,  74 
Wood  ashes,  219 
Woolstapler,  287,  436 


Working  in  rounds,  118 

of  the  turret  drier,  159 
on  the  beam,  124 
Works,  methods  in  up-to-date  leather, 

372 
Wormwood,  Eussia,  289 

YEAST,  296 
Yellow  dye,  300 
Yellow  methanil,  302 
naphthol,  304 
naphtholine.  302 
Young  oak-bark,  53 
Yufts  Russia  leather,  279 

7  INC,  borateof,  264 
^        chloride  of,  264 

sulphate  of,  264 

vitriol,  350 


THE  END 


FK1NTBD   BT    WILLIAM   CLOWES   AND  SONS,  LIMITED,  LONDON  AND  BKCCLB8. 


STATIONERS'  HALL  COURT,  LONDON,  E.C. 

CROSBY  LOCKWOOD  &  SON'S 

CATALOGUE  OF 

SCIENTIFIC    TECHNICAL 

AND 

INDUSTRIAL  BOOKS 


D.  VAN   NOSTRAND   COMPANY 

Sole  Agents  for  the  United  States 


PAGE 
MECHANICAL  ENGINEERING.     1 

CIVIL  ENGINEERING II 

MARINE  ENGINEERING,  &c.  .    19 

MINING  &  METALLURGY 22 

COLLIERY  WORKING,  &c.  . .  .   26 

ELECTRICITY .28 

ARCHITECTURE  &  BUILDING.  31 
SANITATION  &  WATER  SUP- 
PLY    35 

CARPENTRY  &  TIMBER 36 


PAGE 

DECORATIVE  ARTS 38 

NATURAL  SCIENCE.  .  40 

CHEMICAL  MANUFACTURES.   41 

INDUSTRIAL  ARTS 43 

COMMERCE,  TABLES,  &c 49 

AGRICULTURE    &    GARDEN- 

ING.  50 

MATHEMATICS      &     ARITH- 
METIC. .  .54 
LAW  &  MISCELLANEOUS.  .  .     56 


MECHANICAL  ENGINEERING,   ETC. 


THE   MECHANICAL   HANDLING   OF   MATERIAL. 

A  Treatise  on  the  Handling  of  Material,  such  as  Coal,  Ore,  Timber,  etc., 
by  Automatic  or  Semi-automatic  Machinery,  together  with  the  Various 
Accessories  used  in  the  Manipulation  of  such  Plant,  and  Dealing  fully 
with  the  Handling,  Storing,  and  Warehousing  of  Grain.  By  G.  F. 
ZIMMER,  A.M.Inst.C.E.  528  pages.  Royal  8vo,  cloth,  with  550  Illus- 
trations (including  Folding  Plates)  specially  prepared  for  the  Work 

CONTENTS: — CHAPTER  I.  INTRODUCTORY. — II.  ELEVATORS. — III.  WORM 
CONVEYORS. — IV.  PUSH-PLATE  OR  SCRAPER  CONVEYORS. — V.  TROUGH 
CABLK  CONVEYORS. — VI.  BAND  CONVEYORS. — VII.  METAL  BAND  CON- 
VEYORS.— VIII.  PICKING  BELTS  OR  TABLES  WITH  OR  WITHOUT  LOWERING 
ENDS  OR  SHOOTS.  IX.  THE  CONTINUOUS  TROUGH  OR  TRAVELLING  TROUGH 
CONVEYOR. — X.  VIBRATING  TROUGH  CONVEYORS. — XI.  TIGHTENING  GEAR 
FOR  ELEVATORS  AND  CONVEYORS,  AND  DRIVING  POWER  REQUIRED  FOR  DIF- 
FERENT TYPES  OF  CONVEYORS. — XII.  THE  TRAVELLING  OR  TILTING  BUCKET 
CONVEYORS. — XIII.  PNEUMATIC  ELEVATORS  AND  CONVEYORS. — XIV.  CON- 
VEYORS DESIGNED  FOR  SPECIAL  PURPOSES,  INCLUDING  THE  BOLINDER  TlMBER 

CONVEYOR,  COKE  CONVEYORS,  AND  CASTING  MACHINES. — XV.  ENDLESS 
CHAIN  AND  ROPE  HAULAGE. — XVI.  ROPEWAYS  AND  AERIAL  CABLEWAYS, 
INCLUDING  ROPEWAYS,  CABLEWAYS,  AND  APPLIANCES  FOR  COALING  AT  SEA. — 
XVII.  UNLOADING  APPLIANCES,  INCLUDING  METHODS  OF  DISCHARGING  BY 

MEANS  OF  SKIPS  AND  GRABS. XVIII.    DISCHARGING  VESSELS  AND  BARGES 

BY  MEANS  OF  ELEVATORS. XIX.  UNLOADING  BY  MEANS  OF  SPECIALLY  CON- 
STRUCTED SELF-EMPTYING  BOATS  AND  BARGES. — XX.  UNLOADING  BY  MEANS 
OF  SPECIALLY  CONSTRUCTED  SELF-EMPTYING  RAILWAY  TRUCKS. — XXI.  UN- 
LOADING BY  MEANS  OF  COAL  TlPS. XXII.  COLLIERY  TlPPLERS. XXIII. 

MISCELLANEOUS  LOADING  AND  UNLOADING  DEVICES. — XXIV.  AUTOMATIC 
LOADING  DEVICES. — XXV.  THE  AUTOMATIC  WEIGHING  OF  MATERIAL. — 
XXVI.  COALING  OF  RAILWAY  ENGINES. — XXVII.  COAL-HANDLING  PLANT 


2         CROSBY  LOCKWQOD  &>  SON'S  CATALOGUE. 

FOR  GAS-WORKS,  POWER  STATIONS,  BOILER-HOUSES,  ETC. — XXVIII.  FLOOR 
AND  SILO  WAREHOUSES  FOR  GRAINS  AND  SEEDS. — XXIX.  COAL  STORES  AND 
COAL  SILOS. — XXX.  HIGH-LEVEL  CRANES. — INDEX. 

HOISTING   MACHINERY. 

An  Elementary  Treatise  on.  Including  the  Elements  of  Crane  Con- 
struction and  Descriptions  of  the  Various  Types  of  Cranes  in  Use.  By 
JOSEPH  HORNER,  A.M.I.M.E.,  Author  of  " Pattern -M aking  "  and  other 
Works.  Crown  8vo,  with  215  Illustrations,  including  Folding  Plates, 
cloth $3.00 

AERIAL   OR   WIRE=ROPE   TRAMWAYS. 

Their   Construction    and    Management.     By   A.    J.    WALLIS-TAYLER, 

A.M.Inst.C.E.     With  81  Illustrations.      12mo,  cloth $3.0O 

' '  An  excellent  volume ,  and  a  very  good  exposition  of  the  various  systems 
of  rope  transmission  in  use  and  gives  as  well  not  a  little  valuable  informa- 
tion about  their  working,  repair,  and  management.  We  can  safely  recom- 
mend it  as  a  useful  general  treatise  on  the  subject." — Engineer. 

MODERN   MILLING    MACHINES. 

Their  Design,  Construction,  and  Working.  A  Handbook  for  Practical 
Men  and  Engineering  Students.  By  JOSEPH  HORNER,  A.M.I.Mech.E., 
Author  of  "Pattern-Making,"  etc.  With  269  Illustrations.  Demy 
8vo,  cloth.  [.Just  Ready.] $4.00 

TOOLS   FOR    ENGINEERS   AND   WOODWORKERS. 

A  Practical  Treatise  including  Modern  Instruments  of  Measurement. 

By  JOSEPH  HORNER,  A.M.Inst.M.E.,  Author  of  "Pattern-Making,"  etc. 

Demy,  8vo,  with  456  Illustrations $3.0O 

SUMMARY  OF  CONTENTS: — INTRODUCTION. — GENERAL  SURVEY  OF  TOOLS. — 
TOOL  ANGLES. — SEC.  I.  CHISEL  GROUP. — CHISELS  AND  APPLIED  FORMS  FOR 
WOODWORKERS. — PLANES. — HAND  CHISELS  AND  APPLIED  FORMS  FOR  METAL 
WORKING.— CHISEL-LIKE  TOOLS  FOR  METAL  TURNING,  PLANING,  ETC. — 
SHEARING  ACTION  AND  SHEARING  TOOLS. — SEC.  II.  EXAMPLES  OF  SCRAPING 
TOOLS. — SEC.  III.  TOOLS. — RELATING  TO  CHISELS  AND  SCRAPERS. — SAWS. — 
FILES. — MILLING  CUTTERS. — BORING  TOOLS  FOR  WOOD  AND  METAL. — TAPS 
AND  DIES. — SEC.  IV.  PERCUSSIVE  AND  MOULDING  TOOLS. — PUNCHES,  HAM- 
MERS AND  CAULKING  TOOLS. — MOULDING  AND  MODELLING  TOOLS. — MISCEL- 
LANEOUS TOOLS. — SEC.  V.  HARDENING,  TEMPERING,  GRINDING,  AND  SHARP- 
ENING.— SEC.  VI.  TOOLS  FOR  MEASUREMENT  AND  TEST. — STANDARDS  OF 
MEASUREMENT. — SQUARES,  SURFACE  PLATES,  LEVELS,  BEVELS,  PROTRAC- 
TORS, &c. — SURFACE  GAUGES  OR  SCRIBING  BLOCKS. — COMPASSES  AND  DIVI- 
DERS.— CALIPERS,  VERNIER  CALIPERS,  AND  RELATED  FORMS. — MICROMETER 
CALIPERS. — DEPTH  GAUGES  AND  ROD  GAUGES. — SNAP,  CYLINDRICAL  AND 
LIMIT  GAUGES. — SCREW  THPEAD,  WIRE  AND  REFERENCE  GAUGES. — INDI- 
CATORS, ETC. 

ENGINEERS'   TURNING    IN    PRINCIPLE  &  PRACTICE. 

A  Handbook  for  Working  Engineers,  Technical  Students,  and  Amateurs. 

By  JOSEPH  HORNER,  A.M.I.Mech.E.,  Author  of  "Pattern-Making,"  etc. 

8vo,  cloth,  with  488  Illustrations S3.0O 

SUMMARY  OF  CONTENTS: — INTRODUCTION. — RELATIONS  OF  TURNERY  AND 
MACHINE  SHOP. — SEC.  I.  THE  LATHE,  ITS  WORK,  AND  TOOLS. — FORMS  AND 
FUNCTIONS  OF  TOOLS.  REMARKS  ON  TURNING  IN  GENERAL. — SEC.  II.  TURN- 
ING BETWEEN  CENTRES. — CENTRING  AND  DRIVING. — USE  OF  STEADIES. — 
EXAMPLES  OF  TURNING  INVOLVING  LINING-OUT  FOR  CENTRES.— MANDREL 
WORK. — SEC.  III.  WORK  SUPPORTED  AT  ONE  END. — FACE  PLATE  TURNING. 
ANGLE  PLATE  TURNING. — INDEPENDENT  JAW  CHUCKS. — CONCENTRIC,  UNI- 
VERSAL, TOGGLE,  AND  APPLIED  CHUCKS. — SEC.  IV.  INTERNAL  WORK. — 
DRILLING,  BORING,  AND  ALLIED  OPERATIONS. — SEC.  V.  SCREW  CUTTINGS 
AND  TURRET  WORK. — SEC.  VI.  MISCELLANEOUS.: — SPECIAL  WORK. —  MEAS- 
UREMENT, GRINDING.— TOOL  HOLDERS. — SPEED  AND  FEEDS,  TOOL  STEEL. — 
STEEL  MAKERS'  INSTRUCTIONS. 


MECHANICAL  ENGINEERING,  &c.  3 

THE  MECHANICAL  ENGINEERS'  REFERENCE  BOOK. 

For  Machine  and  Boiler  Construction.  In  Two  Parts.  Part  I.  GEN- 
ERAL ENGINEERING  DATA.  Part  II.  BOILER  CONSTRUCTION.  With 
51  Plates  and  numerous  Illustrations.  By  NELSON  FOLEY,  M.I.N.A. 
Third  Edition,  Revised  throughout,  and  much  Enlarged.  Folio,  half- 
bound In  Press 

PART  I:  MEASURES. — CIRCUMFERENCES  AND  AREAS,  Ac. — SQUARES, 
CUBES,  FOURTH  POWERS. — SQUARE  AND  CUBE  ROOTS. — SURFACE  OF  TUBES. 
— RECIPROCALS.— LOGARITHMS. — MENSURATION. — SPECIFIC  GRAVITIES  AND 
WEIGHTS. — WORK  AND  POWER. — HEAT. — COMBUSTION. — EXPANSION  AND 
CONTRACTION. — EXPANSION  OF  GASES. — STEAM. — STATIC  FORCES. — GRAVI- 
TATION AND  ATTRACTION. — MOTION  AND  COMPUTATION  OF  RESULTING 
FORCES. — ACCUMULATED  WORK. — CENTRE  AND  RADIUS  OF  GYRATION. — 
MOMENT  OF  INERTIA. — CENTRE  OF  OSCILLATION. — ELECTRICITY. — STRENGTH 
OF  MATERIALS. — ELASTICITY. — TEST  SHEETS  OF  METALS. — FRICTION. — 
TRANSMISSION  OF  POWER. — FLOW  OF  LIQUIDS. — FLOW  OF  GASES. — AIR 
PUMPS,  SURFACE  CONDENSERS,  &c. — SPEED  OF  STEAMSHIPS. — PROPELLERS. — 
CUTTING  TOOLS. — FLANGES.— -COPPER  SHEETS  AND  TUBES. — SCREWS,  NUTS, 
BOLT  HEADS,  Ac. — VARIOUS  RECIPES  AND  MISCELLANEOUS  MATTER. — WITH 
DIAGRAMS  FOR  VALVE-GEAR,  BELTING  AND  ROPES,  DISCHARGE  AND  SUC- 
TION PIPES,  SCREW  PROPELLERS,  AND  COPPER  PIPES. 

PART  II:  TREATING  OF  POWER  OF  BOILERS. — USEFUL  RATIOS — NOTES 
ON  CONSTRUCTION. — CYLINDRICAL  BOILER  SHELLS. — CIRCULAR  FURNACES. 
FLAT  PLATES. — STAYS. — GIRDERS. — SCREWS. — HYDRAULIC  TESTS. — RCVET- 
ING. — BOILER  SETTING,  CHIMNEYS,  AND  MOUNTINGS. — FUELS,  Ac. — EXAM- 
PLES OK  BOILERS  AND  SPEEDS  OF  STEAMSHIPS. — NOMINAL  AND  NORMAL 
HORSE  POWER. — WITH  DIAGRAMS  FOR  ALL  BOILER  CALCULATIONS  AND 
DRAWINGS  OF  MANY  VARIETIES  OF  BOILERS. 

THE   WORKS'  MANAGER'S   HANDBOOK. 

Comprising  Modern  Rules,  Tables,  and  Data.  For  Engineers,  Mill- 
wrights, and  Boiler  Makers;  Tool  Makers,  Machinists,  and  Metal 
Workers;  Iron  and  Brass  Founders,  etc.  By  W.  S.  HUTTON,  Civil 
and  Mechanical  Engineer,  Author  of  "The  Practical  Engineer's  Hand- 
book." Sixth  Edition,  carefully  Revised  and  Enlarged.  8vo,  strongly 

bound  $6.00 

fW~  The  Author  having  compiled  Rules  and  Data  for  hit  own  use  in  a  great 
variety  of  modern  engineering  work,  and  having  found  his  notes  extremely  use- 
ful, decided  to  publish  them — revised  to  date — believing  that  a  practical  work, 
suited  to  the  DAILY  REQUIREMENTS  OF  MODERN  ENGINEERS,  would  be  favorably 
received. 

"The  Author  treats  every  subject  from  the  point  of  view  of  one  who  has 
collected  worksh9p  notes  for  application  in  workshop  practice,  rather  than 
from  the  theoretical  or  literary  aspect.  The  volume  contains  a  great  deal 
of  that  kind  of  information  which  is  gained  only  by  practical  experience 
and  is  seldom  written  in  books." — The  Engineer. 

STEAM    BOILER   CONSTRUCTION. 

A  Practical  Handbook  for  Engineers,  Boiler-makers,  and  Steam  Users. 
Containinga  large  Collection  of  Rules  and  Data  relating  to  Recent  Prac- 
tice in  the  Design,  Construction,  and  Working  of  all  Kinds  of  Stationary, 
Locomotive,  and  Marine  Steam-boilers.  By  WALTER  S.  HUTTON, 
Civil  and  Mechanical  Engineer,  Author  of  "The  Works'  Manager's 
Handbook,"  "The  Practical  Engineer's  Handbook,"  &c.  With  up- 
wards of  500  Illustrations.  Fourth  Edition,  carefully  Revised  and 

Enlarged.     8vo,  over  680  pages,  cloth,  strongly  bound &S.09 

t3P"This  Work  is  issued  in  continuation  of  the  series  of  handbooks 
written  by  the  Author,  viz:  "THE  WORKS'  MANAGER'S  HANDBOOK"  and 
"THE  PRACTICAL  ENGINEER'S  HANDBOOK,"  which  are  so  highly  appreciated 
by  engineers  for  the  practical  nature  of  their  information,  and  is  consequently 
written  in  the  same  style  as  those  works. 

CONTENTS:  —  HEAT,  RADIATION,  AND  CONDUCTION,  NON-CONDUCTIN° 
MATERIALS,  AND  COVERINGS  FOR  STEAM  BOILERS. — COMPOSITION,  CALORIFIC 
POWER,  AND  EVAPORATIVE  POWER  OF  FUELS. — COMBUSTION,  FIRING  STEAM 
BOILERS,  PRODUCTS  OF  COMBUSTION,  <fec. — CHIMNEYS  FOR  STEAM  BOILERS. — 


4          CROSBY  LOCKWOOD  6-  SON'S  CATALOGUE. 

STEAM  BLAST.' — FORCE  DRAUGHT."-FEED  WATER. — EFFECT  OF  HEAT  ON 
WATER. — EXPANSION  OF  WATER  BY  HEAT. — WEIGHT  OF  WATER  AT  DIFFER- 
ENT TEMPERATURES.  —  CONVECTION.  —  CIRCULATION.  —  EVAPORATION. — 
PROPERTIES  OF  SATURATED  STEAM. — EVAPORATIVE  POWER  OF  BOILERS. — 
PRIMING,  &c. — WATER-HEATING  SURFACES  OF  STEAM  BOILERS. — TRANS- 
MISSION OF  HEAT. — SMOKE  TUBES. — EVAPORATIVE  POWERS  AND  EFFI- 
CIENCY OF  BOILERS. — WATER  CAPACITY  AND  STEAM  CAPACITY  OF  BOILERS. — 
FIRE-GRATES,  FIRE-BRIDGES,  AND  FIRE-BARS. — POWER  OF  BOILERS. — 
CYLINDRICAL  SHELLS  AND  FURNACE-TUBES  OF  BOILERS,  &c. 

TESTS  OF  MATERIALS. — STRENGTH  AND  WEIGHT  OF  BOILER-PLATES. — 
EFFECT  OF  TEMPERATURE  ON  METALS. — RIVET  HOLES. — RIVETS. — RIVET 
JOINTS  OF  STEAM  BOILERS. — CAULKING. — ENDS  OF  CYLINDRICAL  SHELLS. — 
STAYS  FOR  BOILERS,  &c. — STEAM  GENERATORS. — DESCRIPTION  AND  PRO- 
PORTIONS OF  CORNISH,  LANCASHIRE,  AND  OTHER  TYPES  OF  STATIONARY 
BOILERS.  —  BOILER  SETTING.  —  MULTITUBULAR  BOILERS. —  LOCOMOTIVE 
BOILERS. — PORTABLE  BOILERS. — MARINE  BOILERS. — VERTICAL  BOILERS. — 
WATER-TUBE  BOILERS. — SUPERHEATERS. — COST  OF  STEAM  PRODUCTION. — 
FURNACES  FOR  REFUSE  FUELS. — DESTRUCTORS,  &c. 

SAFETY-VALVES. — STEAM  PIPES. — STOP- VALVES,  AND  OTHER  MOUNTINGS 
FOR  BOILERS. — FEED  PUMPS. — STEAM  PUMPS. — FEED-WATER  CONSUMPTION. 
— INJECTORS. — INCRUSTATION  AND  CORROSION. — FEED-WATER  HEATERS. — 
EVAPORATORS.  —  TESTING  BOILERS.  —  EVAPORATIVE  PERFORMANCES  OF 
STEAM  BOILERS.  STEAM-BOILER  EXPLOSIONS,  &c. 

PLATING    AND    BOILER    MAKING. 

A  Practical  Handbook  for  Workshop  Operations.     By  JOSEPH  G.  HOR- 

NER,  A.M.I.M.E.     380  pp.  with  338  Illustrations.     12mo  cloth.  $3.OO 

CONTENTS: — THE  TRADE. — TOOLS. — MATERIALS. — TESTING  MATERIALS. — 

LIMITING    DIMENSIONS    AND    WEIGHTS    OF    MATERIALS. — CUTTING    AND 

STRAIGHTENING  PLATES,  &c. — BENDING  PLATES. — BENDING  ANGLES,  &c. — 

WELDING. —  FLANGING.  —  PUNCHING.  —  RIVETING.  —  TYPES  OF  RIVETED 

JOINTS. — ESTIMATION  OF  LENGTHS  OF  MATERIAL. — THE  MARKING  OUT  OF 

WORK. — THE  ESTIMATION  OF  WEIGHTS,  &c. — MACHINES. 

A   TREATISE  ON    STEAM    BOILERS. 

Their  Strength,  Construction,  and  Economical  Working.  By  R.  WIL- 
SON, C.E.  Fifth  Edition.  12mo,  cloth $2.50 

"The  best  treatise  that  has  ever  been  published  on  steam  boilers." — En- 
gineer. 

BOILER  AND  FACTORY  CHIMNEYS. 

Their  Draught-Power  and  Stability.  With  a  chapter  on  Lightning  Con- 
ductors. By  ROBERT  WILSON,  A.I. C.E. ,  Author  of  "A  Treatise  on 
Steam  Boilers,"  etc.  12mo,  cloth $1.50 

BOILERMAKER'S   ASSISTANT 

In  Drawing,  Templating,  and  Calculating  Boiler  Work,  etc.  By  J. 
COURTNEY,  Practical  Boilermaker.  Edited  by  D.  K.  CLARK,  C.E. 
Seventh  Edition.  12mo,  cloth .80 

BOILERMAKER'S    READY    RECKONER. 

With  Examples  of  Practical  Geometry  and  Templating  for  the  Use  of 
Platers,  Smiths,  and  Riveters.  By  JOHN  COURTNEY.  Edited  by  D. 
K.  CLARK,  M.Inst.C.E.  Crown  8vo,  cloth $1.60 

BOILERMAKER'S    READY  RECKONER   &  ASSISTANT. 

With  Examples  of  Practical  Geometry  and  Templating  for  the  Use  of 
Platers,  Smiths,  and  Riveters.  By  JOHN  COURTNEY.  Edited  by  D.  K. 
CLARK,  M.Inst.C.E.  Fifth  Edition,  480  pp.,  with  140  Illustrations. 
Fcap.  8vo,  half-bound $3.00 

***  This  Work  consists  of  the  two  previous-mentioned  volumes,  "BOILER- 
MAKER'S ASSISTANT"  and  "BOILERMAKER'S  READY  RECKONER,"  bound 
together  in  One  Volume, 


MECHANICAL  ENGINEERING,  &c.  5 

STEAM    BOILERS. 

Their  Construction  and  Management.  By  R.  ARMSTRONG,  C.E.  Illus- 
trated. Crown  8vo,  cloth 454) 

THE    PRACTICAL    ENGINEER'S   HANDBOOK. 

Comprising  a  Treatise  on  Modern  Engine*  and  Boilers;  Marine.  Loco- 
motive, and  Stationary.  And  containing  a  large  collection  of  Rules  and 
Practical  Data  relating  to  Recent  Practice  in  Designing  and  Construct- 
ing all  kinds  ,.f  Engines,  Boilers,  and  other  Engineering  Work.  Tne 
wnole  constituting  a  comprehensive  Key  to  the  Board  of  Trade  and 
•  it  I.IT  Examinations  for  Certificates  of  Competency  in  Modern  Mechan- 
ical Engineering.  By  WALTER  S.  HUTTON,  Civil  and  Mechanical  En- 
gineer, Autnor  of  "The  Works'  Manager's  Handbook  for  Engineers," 
dec.  With  upwards  of  420  Illustrations.  Sixth  .xiition,  lie  vised  and 

Enlarged.     Medium  8vo.  nearly  500  pp..  strongly  oound S7.OO 

tdV'  This  Work  it  designed  a»  a  companion  to  the  Author's  *' WORKS' 
MANAGER'S  HANDBOOK."  It  possesses  many  new  and  original  feature*,  and 
contains,  like  it*  predecessor,  a  quantity  of  matter  not  originally  intended  for 
publication,  but  collected  by  the  Author  for  hit  own  use  in  the  construction  of  a 
great  variety  of  MODERN  ENGINEERING  WORK. 

The  informal  i.  :n  is  given  in  a  condensed  and  concise  form,  and  is  illus- 
trated by  upwards  <.  f  420  Engravings;  and  comprises  a  quantity  of  tabulated 
matter  of  great  value  io  all  engaged  in  designing,  constructing,  or  estimating  for 
ENGINES,  BOILERS,  and  OTHER  ENGINEERING  WORK. 

TEXT-BOOK   ON    THE    STEAM    ENGINE. 

With  a  Supplement  on  GAS  ENGINES  and  PART  II.  on  HEAT  ENGINES 
By  T.  M.  GOODBYE,  M. A.,  Barrister  at  Law.  Professor  of  Mechanic*  at 
the  Royal  College  of  Science.  London;  Author  of  "The  Principles  of 
Mechanics,"  "The  Elements  of  Mechanism,"  Ac.  Fourteenth  Edition. 

Crown  8vo,  cloth. .  .  $£.().) 

"  Professor  Goodeve  has  given  us  a  treatise  on  the  steam  engine  which  will 

bear  comparison  with  anything  written  by  Huxley  or  Maxwell,  and  we  can 

award  it  no  higher  praise." — Engineer. 

A   HANDBOOK   ON   THE   STEAM    ENGINE. 

With  especial  Reference  to  Small  and  Medium  sised  Engines.  For  the 
Use  of  Engine  Makers,  Mechanical  Draughtsmen,  Engineering  Students, 
and  users  of  Steam  Power.  By  HKRMAN  HAEDER,  C.E.  Translated 
from  the  German,  with  additions  and  alterations,  by  H.  H.  P.  POWLES, 
A.M.I.C.E.,  M.I.M.E.  Third  Edition.  Revised.  With  nearly  1.100 

Illustrations.     12mo,  cloth .  .  S3.OO 

SUMMARY  OF  CONTENTS. — INTRODUCTION. — TYPES  or  STEAM  ENGINES. — 
DETAIL*  OF  STEAM  ENGINES. — GOVERNORS. — VALVE  GEARS. — CONDENSERS, 
AIR- PUMPS,  AND  FEED-PUMPS. — EXAMPLES  OF  ENGINES  OF  CONTINENTAL 
MARK,  FROM  ACTUAL  PRACTICE. — PARTICULARS  OF  ENGINES  BY  ENGLISH 
M  \KKIIS. — COMPOUND  ENGINES. — INDICATOR  AND  INDICATOR  DIAGRAMS. — 
CALCULATIONS  FOR  POWKR  AND  STEAM  CONSUMPTION. —  EFFECT  OF  INERTIA 
ON  RECIPROCATING  PARTS  OF  ENGINES. — FRICTION  BRAKE  DYNAMOMETER — 
SUNDRY  DETAILS. — BOILERS. — INDEX. 

"  There  can  be  no  question  as  to  its  value.  We  cordially  commend  it 
to  all  concerned  in  the  design  and  construction  of  the  steam  engine." — 
Mechanical  World. 

THE    PORTABLE    ENGINE. 

A  Practical  Manual  on  its  Construction  and  Management,  for  the  use 
of  Owners  and  Users  of  Steam  Engines  generally.  By  WILLIAM  DYSON 

WANSBROUGH.  12mo,  cloth St. 50 

"This  is  a  work  of  value  to  those  who  use  steam  machinery.  .  .  .  Should 

be  read  by  every  one  who  has  a  steam  engine,  on  a  farm  or  elsewhere. "— 

Mark  Lane  Express. 


6         CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
THE   STEAM    ENGINE. 

A  Treatise  on  the  Mathematical  Theory  of,  with  Rules  and  Examples 
for  Practical  Men.  By  T.  BAKER,  C.E.  12mo,  cloth 60 

"Teems  with  scientific  information  with  reference  to  the  steam-engine." — 
Design  and  Work. 

THE   STEAM    ENGINE. 

For  the  use  of  Beginners.     By  Dr.  LARDNER.     12mo,  cloth. .  .       .(JO 

LOCOMOTIVE    ENGINE   DRIVING. 

A  Practical  Manual  for  Engineers  in  Charge  of  Locomotive  Engines. 
By  MICHAEL  REYNOLDS,  M.S.E.  Twelfth  Edition.  12mo,  cloth 

boards....  $2.00 

"We  can  confidently  recommend  the  book,  not  only  to  the  practical  driver, 

but  to  every  one  who  takes  an  interest  in  the  performance  of  locomotive 

engines." — The  Engineer. 

THE   LOCOMOTIVE   ENGINE. 

The  Autobiography  of  an  Old  Locomotive  Engine.  By  ROBERT 
WEATHERBURN,  M.I.M.E.  With  Illustrations  and  Portraits  of  GEORGE 
and  ROBERT  STEPHENSON.  12mo,  cloth $1.00 

THE  LOCOMOTIVE  ENGINE  AND  ITS  DEVELOPMENT. 

A  Popular  Treatise  on  the  Gradual  Improvements  made  in  Railway 
Engines  between  1803  and  1903.  By  CLEMENT  E.  STRETTON,  C.E. 

Sixth  Edition,  Revised  and  Enlarged.  12mo,  cloth $2.OO 

"Students  of  railway  history  and  all  who  are  interested  in  the  evolution 

of  the  modern  locomotive  will  find  much  to  attract  and  entertain  in  this 

volume." — The  Times. 

THE  MODEL  LOCOMOTIVE  ENGINEER, 

Fireman,  and  Engine-Boy.  Comprising  a  Historical  Notice  of  the 
Pioneer  Locomotive  Engines  and  their  Inventors.  By  MICHAEL  REYN- 
OLDS. Second  Edition,  with  Revised  Appendix.  12mo,  cloth.  $2.OO 
"We  should  be  glad  to  see  this  book  in  the  possession  of  every  one  in  the 

kingdom  who  has  ever  laid,  or  is  to  lay,  hands  on  a  locomotive  engine." — 

Iron. 

LOCOMOTIVE    ENGINES. 

A  Rudimentary  Treatise  on.  By  G.  D.  DEMPSEY,  C.E.  With  large 
Additions  treating  of  the  Modern  Locomotive,  by  D.  K.  CLARK, 

M.Inst.C.E.     With  Illustrations.       12mo,  cloth $.120 

"A  model  of  what  an  elementary  technical  book  should  be." — Academy. 

CONTINUOUS   RAILWAY   BRAKES. 

A  Practical  Treatise  on  the  several  Systems  in  Use  in  the  United  King- 
dom; their  Construction  and  Performance.  By  M.  REYNOLDS.  8vo, 
cloth $3.50 

ENGINE-DRIVING   LIFE. 

Stirring  Adventures  and  Incidents  in  the  Lives  of  Locomotive  Engine- 
Drivers.  By  MICHAEL  REYNOLDS.  Third  Edition.  12mo,  cloth.  .60 

STATIONARY   ENGINE   DRIVING. 

A  Practical  Manual  for  Engineers  in  Charge  of  Stationary  Engines.  By 
MICHAEL  REYNOLDS,  M.S.E.  Seventh  Edition.  12mo,  cloth  boards. 

$2.00 

THE    CARE    AND     MANAGEMENT    OF     STATIONARY 

ENGINES. 

A  Practical  Handbook  for  Men-in-charge.  By  C.  HURST.  12mo.        .50 


MECHANICAL  ENGINEERING,  &c.  7 

THE    ENGINEMAN'S   POCKET  COMPANION 

and  Practical  Educator  for  Enginemen,  Boiler  Attendants,  and  Me- 
chanics. By  MICHAEL  REYNOLDS.  With  45  Illustrations  and  numer- 
ous Diagrams.  Fifth  Edition.  Royal  18mo,  strongly  bound  for 
•Pocket  wear.  81.5O 

"A  most  meritorious  work,  giving  in  a  succinct  and  practical  form  all  the 

information  an  engine-minder,  desirous  of  mastering  the  scientific  principles 

of  his  daily  calling,  would  require." — The  Miller. 

THE    SAFE    USE   OF   STEAM. 

Containing  Rules  for  Unprofessional  Steam  Users.  By  an  ENGINEER. 
Eighth  Edition.  Sewed.  .  .  .  .25 

"If  steam-users  would  but  learn  this  little  book  by  heart,  boiler  explo- 
sions would  become  sensations  by  their  rarity." — English  Mechanic. 

STEAM    AND   MACHINERY    MANAGEMENT. 

A  Guide  to  the  Arrangement  and  Economical  Management  of  Machin- 
ery, with  Hints  on  Construction  and  Selection.  By  M.  POWIH  BALK, 
Ml  n-t.  M.K.  12mo.  cloth 81. (N) 

GAS   AND   OIL    ENGINE    MANAGEMENT. 

A  Practical  Guide  for  Users  and  Attendants,  being  Notes  on  Selection, 
Construction,  and  Management.  By  M.  Powis  BALK.  M.Inst.C.E., 
M.I.Mech.E.  Author  of  "Woodworking  Machinery."  Ac.  12mo, 
cloth...  •••1.50 

ON    GAS    ENGINES. 

With  Appendix  describing  a  Recent  Engine  with  Tube  Igniter.  By 
T.  M.  GOODEVE,  M.A.  12mo,  cloth $1 .00 

THE    ENGINEER'S   YEAR-BOOK   FOR    1906. 

Comprising  Formulae.  Rules.  Tables,  Data,  and  Memoranda  in  Civil. 
Mechanical,  Electrical,  Marine,  and  Mine  Engineering.  By  H.  R. 
KEMPK,  M.Inst.C.E..  Principal  Staff  Engineer,  Engineer-m-Chief'a 
Office.  General  Post  Office.  London;  Author  of  "A  Handbook  of  Elec 
trical  Testing,"  "The  Electrical  Engineer's  Pocket-Book. "  Ac.  With 
1,000  Illustrations,  specially  Engraved  for  the  Work.  12mo,  950  pp., 
leather S3.0O 

THE    MECHANICAL    ENGINEER'S    POCKET-BOOK. 

Comprising  Tables,  Formula',  Rules,  and  Data:  a  Handy  Book  of  Ref- 
erence for  Daily  Use  in  Engineering  Practice.     By  D.  KINNEAR  CLARK, 
M.Inst.C.E..  Fifth  Edition,  thoroughly  Revised  and  Enlarged.    By  H.  H. 
P.  POWLES,  A.M.Inst.C.E.,  M.I.M.E.  Small  8vo,  700  pp.,  leather.  S3.OO 
SUMMARY  OF  CONTENTS: — MATHEMATICAL  TABLES. — MEASUREMENT  OF 
SURFACES    AND    SOLIDS. — ENGLISH    WEIGHTS    AND    MEASURES. — FRENCH 
METRIC  WEIGHTS  AND  MEASURES. — FOREIGN  WEIGHTS  AND  MEASURES. — 
MONEYS. — SPECIFIC   GRAVITY,    WEIGHT,    AND    VOLUME. — MANUFACTURED 
METALS. — STEEL  PIPES. — BOLTS  AND  NUTS. — SUNDRY  ARTICLES  IN  WROUGHT 
AND  CAST  IRON,  COPPER,  BRASS,  LEAD,  TIN,  ZINC. — STRENGTH  OF  MATER- 
IALS.— STRENGTH  OF  TIMBER. — STRENGTH  OF  CAST  IRON. — STRENGTH  OF 
WROUGHT  IRON. — STRENGTH  OF  STEEL. — TENSILE  STRENGTH  OF  COPPER, 
LEAD,  Ac. — RESISTANCE  OF  STONES  AND  OTHER  BUILDING  MATERIALS. — 
RIVETED  JOINTS  IN  BOILER  PLATES. — BOILER  SHELLS. — WrfcE  ROPES  AND 
HEMP    ROPES — CHAINS    AND    CHAIN    CABLES. — FRAMING. — HARDNESS    OF 
METALS,  ALLOYS.  AND  STONES. — LABOUR  OF  ANIMALS. — MECHANICAL  PRIN- 
CIPLES.— GRAVITY  AND  FALL  OF  BODIES. — ACCELERATING  AND  RETARDING 
FORCES. — MILLGEARINO,  SHAFTING.  Ac. — TRANSMISSION  OF  MOTIVE  POWER. 

—  HEAT.  —  COMBUSTION. —  FUELS.  —  WARMING,    VENTILATION,    COOKING 
STOVES. — STEAM. — STEAM    ENGINES    AND    BOILERS. — RAILWAYS. — TRAM- 
WAYS.— STEAM  SHIPS. — PUMPING  STEAM  ENGINES  AND  PUMPS. — COAL  GAS. 
G  \s  EVGINKS,  Ac. — AIR  IN  MOTION. — COMPRESSED  AIR. — Hor-AiR  ENGINES. 

—  WATER   POWER. — SPEED   OF  CUTTING  TOOLS. — COLOURS. — ELECTRICAL 
ENGINEERING. 


8          CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
PRACTICAL   MECHANICS'   WORKSHOP   COMPANION. 

Comprising  a  great  Variety  of  the  most  useful  Rules  and  Formulae  in 
Mechanical  Science,  with  numerous  Tables  of  Practical  Data  and  Cal- 
culated Results  for  Facilitating  Mechanical  Operations.  By  WILLIAM 
TEMPLETON,  Author  of  "The  Engineer's  Practical  Assistant,"  &c.»  &c. 
Eighteenth  Edition,  Revised,  Modernised,  and  considerably  Enlarged, 
by  W.  S.  BUTTON,  C.E.,  Author  of  "The  Works'  Manager's  Hand- 
book," &c.  Fcap.  8vo,  nearly  500  pp.,  with  8  Plates  and  upwards  of 
250  Diagrams,  leather $2.50 

ENGINEER'S   AND   MILLWRIGHT'S   ASSISTANT. 

A  Collection  of  Useful  Tables,  Rules,  and  Data.  By  WILLIAM  TEMPLE- 
TON.  Eighth  Edition,  with  Additions.  18mo,  cloth $1.0O 

TABLES       AND    MEMORANDA       FOR        ENGINEERS, 
MECHANICS,  ARCHITECTS,  BUILDERS,  &c. 

Selected  and  Arranged  by  FRANCIS  SMITH.  Seventh  Edition,  Revised, 
including  ELECTRICAL  TABLES,  FORMULAE,  and  MEMORANDA.  Waist- 
coat-pocket size,  limp  leather .60 

THE   MECHANICAL   ENGINEER'S   COMPANION. 

Of  Areas,  Circumferences,  Decimal  Equivalents,  in  inches  and  feet,  mil- 
limetres, squares,  cubes,  roots,  &c.;  Strength  of  Bolts,  Weight  of  Iron, 
&c.;  Weights,  Measures,  and  other  Data.  Also  Practical  Rules  for 
Engine  Proportions.  By  R.  EDWARDS,  M.Inst.C.E.  Fcap.  8vo,  cloth. 

$1.00 
MECHANICAL   ENGINEERING   TERMS. 

(Lockwood's  Dictionary  of).  Embracing  those  current  in  the  Drawing 
Office,  Pattern  Shop,  Foundry,  Fitting,  Turning,  Smiths',  and  Boiler 
Shops,  &c.  Comprising  upwards  of  6,000  Definitions.  Edited  by  J. 
G.  HORNER,  A.M.I.M.E.  Third  Edition,  Revised,  with  Additions. 
12mo,  cloth .' $3.00 

"Just  the  sort  of  handy  dictionary  required  by  the  various  trades  engaged 
in  mechanical  engineering.  The  practical  engineering  pupil  will  find  the 
book  of  great  value  in  his  studies,  and  every  foreman  engineer  and  mechanic 
should  have  a  copy." 

POCKET   GLOSSARY   OF   TECHNICAL   TERMS. 

English-French,  French-English;  with  Tables  suitable  for  the  Archi- 
tectural, Engineering,  Manufacturing,  and  Nautical  Professions.  By 
JOHN  JAMES  FLETCHER.  Fourth  Edition,  200  pp.  Waistcoat-pocket 
size,  limp  leather .60 

IRON   AND   STEEL. 

A  Work  for  the  Forge  Foundry,  Factory,  and  Office.  Containing  ready, 
useful,  and  trustworthy  Information  for  Ironmasters  and  their  Stock- 
takers  ;  Managers  of  Bar,  Rail,  Plate,  and  Sheet  Rolling  Mills ;  Iron  and 
Metal  Founders;  Iron,  Ship, and  Bridge  Builders;  Mechanical,  Mining, 
and  Consulting  Engineers;  Architects,  Contractors,  Builders,  <fec.  By 
CHARLES  HOARE,  Author  of  "The  Slide  Rule,"  &c.  Ninth  Edition. 
32mo,  leather $2.50 

WORKMAN'S  MANUAL  OF  ENGINEERING  DRAWING. 

By  JOHN  MAXTON,  Instructor  in  Engineering  Drawing,  Royal  Naval 
College,  Greenwich.  Eighth  Edition.  300  Plates  and  Diagrams. 
12mo,  cloth...  $1.40 

"A  copy  of  it  should  be  kept  for  reference  in  every  drawing  office." — En- 
gineering. 

PATTERN    MAKING. 

Embracing  the  Main  Types  of  Engineering  Construction,  and  including 
Gearing,  Engine  Work,  Sheaves  and  Pulleys,  Pipes  and  Columns,  Screws, 
Machine  Parts,  Pumps  and  Cocks,  the  Moulding  of  Patterns  in  Loam 
and  Greensand,  Weight  of  Castings,  &c.  By  J.  G.  HORNER,  A.M.I.M.E. 
Third  Edition,  Enlarged.  With 486  Illustrations.  12mo,cloth.$3.00 


MECHANICAL  ENGINEERING,  &c.  9 

SMITHY    AND    FORGE. 

Including  the  Farrier's  Art  and  Coach  Smithing.     By  W.  J.  E.  CRANK. 

12mo,  cloth...  SI  .nil 

"The  fir-t  modern  English  book  on  the  subject.  Great  pains  have  been 
bestowed  by  the  author  upon  the  book;  ahoeing-smiths  will  find  it  both 
useful  and  interesting." 

TOOTHED    GEARING. 

A  Practical  Handbook  for  Offices  and  Workshops.  By  J.  HORNER. 
A.M.I.M.E.  Second  Edition,  with  a  new  Chapter  on  Recent  Practice. 
With  184  Illustrations.  12mo, cloth.  ..  SM/>.-> 

MODERN    WORKSHOP    PRACTICE, 

As  applied  to  Marine,  Land,  and  Locomotive  Engines,  Floating  Docks. 
Dredging  Machines.  Bridges.  Shipbuilding.  *c.  By  J.  G.  WINTON. 
Fourth  Edition,  Illustrated.  12mo.  cloth. ..  81. 1O 

DETAILS   OF    MACHINERY. 

Comprising  Instructions  for  the  Execution  of  various  Work*  in  Iron  in 
the  Fitting  Shop,  Foundry,  and  Boiler  Yard.  By  FRANCIS  CAM  PIN, 
C.E.  12mo,  cloth..  S1.7O 

ENGINEERING   ESTIMATES,  COSTS,  AND  ACCOUNTS. 

A  Guide  to  Commercial  Engineering.  With  numerous  examples  of  Es- 
timates and  Costs  of  Millwright  Work.  Miscellaneous  Production's. 
Steam  Engines  and  Steam  Boilers;  and  a  Section  on  the  Preparation 
of  Costs  Accounts.  By  A  GENERAL  MANAGER.  Second  Edition.  8vo. 
doth..  84.50 

MECHANICAL    ENGINEERING. 

Comprising  Metallurgy,  Moulding.  Casting,  Forging.  Tools,  Workshop 
Machinery,  Mechanical  Manipulation.  Manufacture  of  the  Steam  En- 
gine, Ac.  By  FRANCIS  CAM  PIN,  C.E.  Third  Edition.  12mo,  cloth 

81.00 

LATHE-WORK. 

A  Practical  Treatise  on  the  Tools.  Appliances,  and  Professes  employed  in 
the  Art  of  Turning.  By  PAUL  N.  HASLUCK.  Eighth  Edition.  12mo, 

cloth .....82.00 

"Written  by  a  man  who  knows  not  only  how  work  ought  to  be  done,  but 

who  also  knows  how  to  do  it,  and  how  to  convey  his  knowledge  to  others. "- 

Engineering. 

SCREW-THREADS, 

And  Methods  of  Producing  Them.  With  numerous  Tables  and  com- 
plete Directions  for  using  Screw-cuttingLathes.  By  PAUL  N.  H ASLCCK. 
Author  of  "Lathe-work,"  Ac.  Sixth  Edition.  Waist  coat -pocket  sir*. 

.60 

"Full  of  useful  information,  hints  and  practiral  criticism.  Tans,  dies, 
and  screwing  tools  generally  are  illustrated  and  their  action  described." 

CONDENSED    MECHANICS. 

A  Selection  of  Formula*,  Rules,  Tables,  and  Data  for  the  Use  of  Engi- 
neering Students,  Ac.  By  W.  G.  C.  HUGHES,  A.M. I.C.E.  12mo,  cloth. 

81.00 
MECHANICS    OF    AIR    MACHINERY. 

By  Dr.  J.  WEISBACH  and  Prof.  G.  HKRRMANN.  Authorised  Translation 
with  an  Appendix  on  American  Practice  by  A.  TBOWBRIDOE,  Ph.B., 
Adjunct  Professor  of  \fechanical  Engineering,  Columbia  University. 
Royal  8vo,  cloth. Net  83.75 


io        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
PRACTICAL   MECHANISM. 

And  Machine  Tools.  By  T.  BAKER,  C.E.  With  Remarks  on  Tools  and 
Machinery  by  J.  NASMYTH,  C.E.  12rao,  cloth $1.00 

MECHANICS. 

Being  a  concise  Exposition  of  the  General  Principles  of  Mechanical 
Science  and  their  Applications.  By  C.  TOMLINSON,  F.R.S.  12mo, 
cloth .60 

FUELS:   SOLID,    LIQUID,    AND   GASEOUS. 

Their  Analysis  and  Valuation.     For  the  use  of  Chemists  and  Engineers. 
By  H.  J.  PHILLIPS,  F.C.S.,  formerly  Analytical  and  Consulting  Chemist 
to  the  Great  Eastern  Railway.    Fourth  Edition.    12mo,  cloth.  .       .80 
"Ought  to  have  its  place  in  the  laboratory  of  every  metallurgical  estab- 
lishment and  wherever  fuel  is  used  on  a  large  scale." — Chemical  News. 

FUEL,    ITS   COMBUSTION    AND    ECONOMY. 

Consisting  of  an  Abridgment  of  "A  Treatise  on  the  Combustion  of  Coal 

and  the  Prevention  of  Smoke."      By  C.  W.  WILLIAMS,  A.Inst.C.E. 

With   extensive    Additions     by    D.    KINNEAR    CLARK,    M.Inst.C.E. 

Fourth  Edition.  I2mo,  cloth $1.50 

"Students  should  buy  the  book  and  read  it,  as  one  of  the  most  complete 
and  satisfactory  treatises  on  the  combustion  and  economy  of  fuel  to  be 
had . ' ' — Engineer. 

STEAM  AND  THE  STEAM  ENGINE, 

Stationary  and  Portable.  Being  an  Extension  of  the  Treatise  on  the 
Steam  Engine  of  Mr.  J.  SEWELL.  By  D.  K.  CLARK,  C.E.  Fourth  Edi- 
tion. 12mo,  cloth $1.40 

"Every  essential  part  of  the  subject  is  treated  of  competently,  and  in  a 
popular  style." 

PUMPS   AND    PUMPING. 

A  Handbook  for  Pump  Users.  Being  Notes  on  Selection,  Construction, 
and  Management.  By  M.  Powis  BALE,  M.Inst.C.E.,  M.I.Mech.E. 

Fourth  Edition.     12mo,  cloth $1.50 

"  Thoroughly  practical  and  clearly  written." 

REFRIGERATION,   COLD   STORAGE,  &    ICE-MAKING. 

A  Practical  Treatise  on  the  Art  and  Science  of  Refrigeration.  By.  A. 
J.  WALLIS-TAYLER,  A.M.Inst.C.E.,  Author  of  "Refrigerating  and  Ice- 
Making  Machinery."  600  pp.,  with  360  Illustrations.  Medium  8vo, 

doth $4.50 

CONTENTS: — CHAPTER  I.  INTRODUCTION. — II.  THE  THEORY  AND  PRAC- 
TICE OF  REFRIGERATION. — III.  THE  LIQUEFACTION  PROCESS. — IV.  THE 
VACUUM  PROCESS. — V.  THE  COMPRESSION  PROCESS  OR  SYSTEM. — VI.  THE 
COMPRESSION  PROCESS  (Continued). — VII.  THE  COMPRESSION  PROCESS  (Con- 
tinued).— VIII.  CONDENSERS  AND  WATER-COOLING  AND  SAVING  APPARATUS. 
— IX.  THE  ABSORPTION  AND  BINARY  ABSORPTION  PROCESS  OR  SYSTEM. — 
X.  THE  COLD-AIR  SYSTEM. — XI.  COCKS,  VALVES  AND  PIPE-JOINTS  AND 
UNIONS. — XII.  REFRIGERATION  AND  COLD  STORAGE. — XIII.  REFRIGERA- 
TION AND  COLD  STORAGE  (Continued). — XIV.  REFRIGERATION  AND  COLD 
STORAGE  (Continued). — XV.  REFRIGERATION  AND  COLD  STORAGE  (Con- 
tinued).— XVI.  MARINE  REFRIGERATION. — XVII.  MANUFACTURING,  IN- 
DUSTRIAL AND  CONSTRUCTIONAL  APPLICATIONS. — XVIII.  ICE-MAKING. — 

XIX.  THE  MANAGEMENT  AND  TESTING  OF  REFRIGERATING  MACHINERY. — 

XX.  COST  OF  WORKING. — XXI.  THE  PRODUCTION  OF  VERY  Low  TEMPER- 
ATURES.— XXII.  USEFUL  TABLES  AND  MEMORANDA. — APPENDIX. — BIBLI- 
OGRAPHY OF  REFRIGERATION. 


CIVIL  ENGINRERTXG,  SURVEYING,  frv.  IT 

THE   POCKET  BOOK  OF  REFRIGERATION  AND   ICE- 
MAKING. 

By  A.  J.  WALLIS-TAYLER,  A.M.Inst.C.E.  Author  of  "Refrigerating 
and  Ire-making  Machinery,"  <tc.  Third  Edition,  Enlarged.  12mo, 
doth..  S!..->0 

REFRIGERATING    &    ICE-MAKING    MACHINERY. 

A  Descriptive  Treatise  for  the  Use  of  Persons  Employing  Refrigerating 
and  Ice-making  Installations,  and  others.  By  A.  J.  WALLIS-TAYLKH, 
A.M.Inst.C.E.  Third  Edition,  Enlarged.  12mo,  cloth  s;.un 

"May  l>e  recommended  as  a  useful  description  of  the  machinery,  the  proc- 
esses, and  of  the  acts,  figures,  and  tabulated  physics  of  refrigerating." — En- 
gineer. 

MOTOR   VEHICLES    FOR   BUSINESS    PURPOSES. 

A  Practical  Handbook  for  those  interested  in  the  Transport  of  Paswn- 
gers  and  Goods.  By  A.  J.  WALLIS-TAYLEP.  A.M.Inst.C.E.  With  134 
Illustrations.  Demy  8 vo,  cloth  .  [Jutt  publithtd.]  £3.54) 

MOTOR  CARS  OR  POWER-CARRIAGES  FOR  COMMON 
ROADS. 

By  A.  J.  WALLIS-TAYLER,  A.M.Inst.C.E.  212  pp.,  with  70  Illustrations. 
12mo,  cloth $2.(M) 

AERIAL   NAVIGATION. 

A  Practical  Handbook  on  the  Construction  of  Dirigible  Balloons,  Afro- 
stats,  Afironlanes,  and  APromotors.  By  FREDERICK  WALKER,  C.E., 
Associate  Member  of  the  Aeronautic  Institute.  With  104  Illustrations. 
Large  12mo,  cloth..  .  .  $.'{.<  M) 

STONE-WORKING    MACHINERY. 

A  Manual  dealing  with  the  Rapid  and  Economical  Conversion  of  Stone. 
With  Hints  on  the  Arrangement  and  Management  of  Stone  Works.  By 
M.  Powis  BALK,  M.Inst.C.E.,  M.I.Mech.E.  Second  Edition,  enlarged. 

12mo,  cloth 8'i.5O 

"The  book  should  be  in  the  hands  of  every  mason  or  student  of  stone- 
work." 

"A  handbook  for  all  who  manipulate  stone  for  building  or  ornamental 
purposes." 

FIRES,  FIRE-ENGINES,    AND    FIRE    BRIGADES. 

With  a  History  of  Fire-Engines,  their  Construction,  Use,  and  Manage- 
ment; Foreign  Fire  Systems;  Hints  on  Fire  Brigades,  4c.  By  C.  F. 
T.  YOUNO,  C.E.  8vo,  cloth S8.0O 

CRANES. 

The  Construction  of.  and  other  Machinery  for  Raising  Heavy  Bodies 
for  the  Erection  of  Buildings,  Ac.  By  J.  GLYNN.  F.R.S.  12mo,  cloth. 

.60 


CIVIL  ENGINEERING,   SURVEYING,   ETC. 
PIONEER    IRRIGATION. 

A  Manual  of  Information  for  Farmers  in  the  Colonies.  By  E.  O.  MAW- 
RON,  M.Inst.C.E.,  Executive  Engineer,  Public  Works  Department, 
Bombay.  With  Additional  Chapters  on  Light  Railways  by  E.  R. 
CALTHROP,  M.Inst.C.E..  M.I.M.E.  Illustrated  by  numerous  Plates 

and  Diagrams.     Demy  8vo,  cloth  .  .  s  1   <  u  > 

SUMMARY  or  CONTENTS: — VALUE  OF  IRRIGATION,  AND  SOURCES  OF  WATKR 
SUPPLY. — DAMS  AND  WEIRS. — CANALS. — UNDERGROUND  WATER. — METH- 
ODS OF  IRRIGATION. — SEWAGE  IRRIGATION. — IMPERIAL  AUTOMATIC  SLUICE 
GATES. — THE  CULTIVATION  OF  IRRIGATED  CROPS,  VEGETABLES,  AND  FRUIT 
TREES. — LIGHT  RAILWAYS  FOR  HEAVY  TRAFFIC. — USEFUL  MEMORANDA  AND 
DATA. 


12        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
THE  RECLAMATION  OF  LAND  FROM  TIDAL  WATERS. 

A  Handbook  for  Engineers,  Landed  Proprietors,  and  others  interested 
in  Works  of  Reclamation.  By  A.  BEAZELY,  M.Inst.C.E.  8vo,  cloth. 

$4.00 

"The  book  shows  in  a  concise  way  what  has  to  be  done  in  reclaiming  land 
from  the  sea,  and  the  best  way  of  doing  it.  Contains  a  great  deal  of  prac- 
tical and  useful  information  which  cannot  fail  to  be  of  service  to  engineers 
entrusted  with  the  enclosure  of  salt  marshes,  and  to  landowners  intending 
to  reclaim  land  from  the  sea." — The  Engineer. 

THE   WATER   SUPPLY   OF   TOWNS   AND   THE   CON- 
STRUCTION OF  WATER-WORKS. 

A  Practical  Treatise  for  the  Use  of  Engineers  and  Students  of  Engineer- 
ing.    By  W.  K.  BURTON,  A.M.Inst.C.E.,  Consulting  Engineer  to  the 
Tokyo  Water- works.     Second  Edition,  Revised  and  Extended.    With 
numerous  Plates  and  Illustrations.    Super-royal  8vo,  buckram.  $9.00 
I.  INTRODUCTORY. — II.  DIFFERENT  QUALITIES  OF  WATER. — III.  QUAN- 
TITY OF  WATER  TO  BE  PROVIDED. — IV.  ON  ASCERTAINING  WHETHER  A  PRO- 
POSED SOURCE  OF  SUPPLY  is  SUFFICIENT. — V.  ON  ESTIMATING  THE  STORAGE 
CAPACITY  REQUIRED  TO  BE  PROVIDED. — VI.  CLASSIFICATION  OF  WATER- 
WORKS.— VII.  IMPOUNDING  RESERVOIRS. — VIII.  EARTHWORK  DAMS. — IX. 
MASONRY  DAMS. — X.  THE  PURIFICATION  OF  WATER. — XI.  SETTLING  RES- 
ERVOIRS.— XII.  SAND   FILTRATION. — XIII.  PURIFICATION   OF  WATER   BY 
ACTION  OF  IRON,  SOFTENING  OF  WATER  BY  ACTION  OF  LIME,  NATURAL 
FILTRATION. — XIV.  SERVICE     OR    CLEAN  WATER     RESERVOIRS — WATER 
TOWERS — STAND  PIPES. — XV.  THE  CONNECTION  OF  SETTLING  RESERVOIRS, 
FILTER  BEDS  AND  SERVICE  RESERVOIRS. — XVI.  PUMPING  MACHINERY. — 

XVII.  FLOW  OF   WATER   IN  CONDUITS — PIPES   AND   OPEN   CHANNELS. — 

XVIII.  DISTRIBUTION  SYSTEMS. — XIX.  SPECIAL  PROVISIONS  FOR  THE  EX- 
TINCTION OF  FIRE. — XX.  PIPES  FOR  WATER-WORKS. — XXI.  PREVENTION 
OF  WASTE  OF  WATER. — XXII.  VARIOUS  APPLIANCES  USED  IN  CONNECTION 
WITH  WATER-WORKS. 

APPENDIX  I.  By  PROF.  JOHN  MILNE,  F.R.S.— CONSIDERATIONS  CON- 
CERNING THE  PROBABLE  EFFECTS  OF  EARTHQUAKES  ON  WATER- WORKS,  AND 
THE  SPECIAL  PRECAUTIONS  TO  BE  TAKEN  IN  EARTHQUAKE  COUNTRIES. 

APPENDIX  II.  By  JOHN  DE  RIJKE,  C.E.— ON  SAND  DUNES  AND  DUNE 
SAND  AS  A  SOURCE  OF  WATER  SUPPLY. 

THE   WATER   SUPPLY   OF   CITIES   AND   TOWNS. 

By  WILLIAM  HUMBER,  A.M.Inst.C.E.,  and  M.Inst.M.E.,  Author  of 
"Cast  and  Wrought  Iron  Bridge  Construction,"  &c.,  &c.  Illustrated 
with  50  Double  Plates,  1  Single  Plate,  Coloured  Frontispiece,  and  up- 
wards of  250  Woodcuts,  and  containing  400  pp.  of  Text.  Imp.  4to, 

elegantly  and  substantially  half-bound  in  morocco $45.00 

Liar  OF  CONTENTS: — I.  HISTORICAL  SKETCH  OF  SOME  OF  THE  MEANS  THAT 

HAVE  BEEN  ADOPTED    FOR  THE  SUPPLY  OF  WATER  TO  ClTIES  AND  TOWNS. 

II.  WATER  AND  THE  FOREIGN  MATTER  USUALLY  ASSOCIATED  WITH  IT. — III. 
RAINFALL  AND  EVAPORATION. — IV.  SPRINGS  AND  THE  WATER-BEARING 
FORMATIONS  OF  VARIOUS  DISTRICTS. — V.  MEASUREMENT  AND  ESTIMATION 

OF  THE  FLOW  OF  WATER. VI.    ON  THE  SELECTION  OF  THE  SOURCE  OF  SUP- 

PLY.  —  VII.  WELLS.  —  VIII.  RESERVOIRS.  —  IX.  THE  PURIFICATION  OF 
WATER.  —  X.  PUMPS.  —  XI.  PUMPING  MACHINERY.  —  XII.  CONDUITS. — 
XIII.  DISTRIBUTION  OF  WATER. — XIV.  METERS,  SERVICE  PIPES,  AND 
HOUSE  FITTINGS. — XV.  THE  LAW  AND  ECONOMY  OF  WATER- WORKS. — XVI. 
CONSTANT  AND  INTERMITTENT  SUPPLY. — XVII.  DESCRIPTION  OF  PLATES. — 
APPENDICES,  GIVING  TABLES  OF  RATES  OF  SUPPLY,  VELOCITIES,  &c.,  &c., 

TOGETHER  WITH  SPECIFICATIONS  OF  SEVERAL  WORKS  ILLUSTRATED,  AMONG 
WHICH  WILL  BE  FOUND:  ABERDEEN,  BlDEFORD,  CANTERBURY,  DUNDEE, 

HALIFAX,  LAMBETH,  ROTHERHAM,  DUBLIN,  AND  OTHERS. 

RURAL   WATER    SUPPLY. 

A  Practical  Handbook  on  the  Sunply  of  Water  and  Construction  of 
Water-works  for  small  Country  Districts.  By  ALLAN  GREENWELL, 
A.M.Inst.C.E.,  and  W.  T.  CURRY,  A.M.Inst.C.E.,  F.G.S.  With  Illus- 
trations. Second  Edition,  Revised.  12mo,  cloth $2.OO 


CIVIL  ENGINEERING,  SURVEYING,  &c.  13 

WATER    ENGINEERING. 

A  Practical  Treatise  of.  the  Measurement.  Storage,  Conveyance,  and 
Utilization  of  Water  for  the  Supply  of  Towns,  for  Mill  Power,  and  for 
other  Purposes.  By  CHARLES  SLAGG,  A.M.Inst.C.E.  •  Second  Edition. 
12mo.  cloth.  .  S:{.<M> 

WATER  WORKS,  FOR  THE  SUPPLY  OF  CITIES  AND 

TOWNS. 

With  a  Description  of  the  Principal  Geological  Formations  of  England 
as  influencing  Supplies  of  Water.  By  SAMUEL  HUGHES.  12mo,  cloth. 

•1.60 

POWER    OF    WATER. 

As  applied  to  drive  Flour  Mills,  and  to  give  motion  to  Turbines,  and 
other  Hydrostatic  Engines.  By  JOSEPH  GLTNN,  F.R.S.,  Ac.  New 
Edition.  Illustrated.  12mo,  cloth.  .  ...........  ,gO 

WELLS   AND   WELL-SINKING. 

By  J.  G.  SWINDELL,  A.R.I.B.A.,  and  G.  R.  BURNELL,  C.E.     Revised 
Edition.     12mo,  cloth  ....................................        ,N4) 

"Solid  practical  information,  written  in  a  concise  and  lucid  style.  The 
work  can  be  recommended." 

HYDRAULIC    POWER    ENGINEERING. 

A  Practical  Manual  on  the  Concentration  and  Transmission  of  Power 
by  Hydraulic  Machinery.  By  G.  CROYDON  MARKS,  A.M.Inst.C.E. 
Second  Edition,  Enlarged,  with  about  240  Illustrations.  8vo.  cloth. 

(Jutt  Published      S3.5Q 

SUMMARY  OF  CONTENTS:  —  PRINCIPLES  or  HYDRAULICS.  —  THE  FLOW  or 
WATER.  —  HYDRAULIC  PRESSURES.  —  MATERIAL.  —  TEST  LOAD.  —  PACKINGS 
FOR  SLIDING  SURFACES.  —  PIPE  JOINTS.  —  CONTROLLING  VALVES.  —  PLATFORM 
LIFTS.  —  WORKSHOP  AND  FOUNDRY  CRANES.  —  WAREHOUSE  AND  DOCK 
CRANES.  —  HYDRAULIC  ACCUMULATORS.  —  FHMM  FOR  BALING  AND  OTHER 
PURPOSES.—  SHEET  METAL  WORKING  AND  FORGING  MACHINERY.  —  HY- 
DRAULIC RIVETERS.  —  HAND  AND  POWKR  PUMPS.  —  STEAM  PUMPS.  —  TUR- 
BINES. —  IMPULSE  TURBINES.  —  REACTION  TURBINES.  —  DESIGN  or  TUR- 
BINES IN  DETAIL.  —  WATER  WHEELS.  —  HYDRAULIC  ENGINES.  —  RECENT 
ACHIEVEMENTS.  —  PRESSURE  or  WATER.  —  ACTION  or  PUMPS,  Ac. 

HYDRAULIC    MANUAL. 

Consisting  of  Working  Tables  and  Explanatory  Text.  Intended  as  a 
Guide  in  Hydraulic  Calculations  and  Field  Operations.  By  Lowis 
D'A.  JACKSON,  Author  of  "Aid  to  Survey  Practice,"  "Modern  Metrol- 


ogy," Ac.     Fourth  Edition,  Enlarged.     8vo,  cloth. 
"The  author  has  constructed  a  manual  which  may  be  accepted  as  a  trust- 
worthy guide  to  this  branch  of  the  engineer's  profession."  —  Engineering. 

HYDRAULIC  TABLES,  CO-EFFICIENTS,  &  FORMUL/E. 

For  Finding  the  Discharge  of  Water  from  Orifices,  Notches,  Weirs, 

Pipes,  and  Rivers.     With  New  Fonnulie.  Tables,  and  General  Informa- 

tion on  Rain-fall,  Catchment-Basins,  Drainage.  Sewerage,  Water  Sup- 

ply for  Towns  and  Mill  Power.      By  JOHN  NEVILLE.  C.E.,  M.R.I.  A- 

Third    Edition,    revised,    with    additions.      Numerous     Illustrations. 

12mo,  cloth.  .  $.->.<  M) 

"It  is,  of  all  English  books  on  the  subject,  the  one  nearest  to  complete- 

ness." 

MASONRY  DAMS  FROM  INCEPTION  TO  COMPLETION. 

Including  numerous  Formulae,  Forms  of  Specifications  and  Tender, 
Pocket  Diagram  of  Forces,  «feo.     For  the  use  of  Civil  and  Mining  En- 
ginee-s.      By  C.  F.  Courtney.  M.  lust  .C.E.     8vo.  cloth  .........  83.50 

"Contains  a  Rood  deal  of  valuable  data.  Many  useful  suggestions  will  be 

fc.  mid  in  the  remarks  on  site  and  position,  location  of  dam,  foundations 

and  const  uct»on."  —  Building  New*. 


i4        CROSBY  LOCKWOOD  &>  SON'S  CATALOGUE. 
RIVER   BARS. 

The  Causes  of  their  Formation,  and  their  Treatment  by  "Induced  Tidal 
Scour'';  with  a  Description  of  the  Successful  Reduction  h.v  this  Method 
of  the  Bar  at  Dublin.  By  I.  J.  MANX,  Assist,  Eng.  to  the  Dublin  Port 

and  Docks  Board.     Royal  8vo,  cloth $3.0O 

"We  recomniend  all  interested  in  harbour  works — and,  indeed,  those  con- 
cerned in  the  improvements  of  rivers  generally — to  read  Mr.  Mann's  inter- 
esting work." — Engineer. 

DRAINAGE   OF   LANDS,    TOWNS,  AND    BUILDINGS. 

By  C..  D.  DEMPSEY,  C.E.  Revised,  with  large  Additions  on  Recent 
Practice  in  Drainage  Engineering  by  D.  KINNEAR  CLARK,  M.inst.C.E. 
Fourth  Edition.  12mo,  cloth $1.80 

SURVEYING    AS    PRACTISED    BY   CIVIL    ENGINEERS 

AND  SURVEYORS. 

Inchiding  the  Setting-out  of  Works  for  Construction  and  Surveys 
Abroad,  with  many  Examples  taken  from  Actual  Practice.  A  Hand- 
book for  use  in  the  Field  and  the  Office,  intended  also  as  a  Text-book 
for  Stvderits.  By  JOHN  WHTTKLAW,  Jun.,  A.M.Inst.C.E.,  Author  of 
"Points  and  Crossings."  With  about  260  Illustrations.  Demy  8vo, 
doth $4.00 

PRACTICAL   SURVEYING. 

A  Text-book  for  Students  preparing  for  Examination  or  for  Survey- 
work  in  the  Colonies.  By  C«EORGE  W.  USII.L,  A.M.Inst.C.E.  Eighth 
Edition,  thoroughly  Revised  and  Enlarged,  by  AIEX  BEAZELEY, 
M.inst.C.E.  With  4  Lithographic  Plates  and  360  Illustrations.  12mo, 
cloth $3.00 

SURVEYING   WITH    THE   TACHEOMETER. 

A  practical  Manual  for  the  use  of  Civil  and  Military  Engineers  and  Sur- 
veyors, including  two  series  of  Tables  specially  computed  for  the  Re- 
duction of  Readings  in  Sexagesimal  -and  in  Centesimal  Degrees.  By 
NEIL  KENNEDY,  M.inst.C.E.  With  Diagrams  and  Plates.  Second 

Edition.     8vo,  cloth $4.00 

"The  work  is  very  clearly  written,  and  should  remove  all  difficulties  in  the 
way  of  any  surveyor  desirous  of  making  use  of  this  useful  and  rapid  instru- 
ment."— Nature. 

LAND   AND    ENGINEERING    SURVEYING. 

For  Students  and  Practical  Use.  Py  T.  BAKER,  C.E.  Twentieth  Edi- 
tion, by  F.  E.  DIXON,  A.M.Inst.C.E.  With  Plates  and  Diagran-s. 
12mo,  cloth .80 

AID   TO    SURVEY    PRACTICE. 

For  Reference  in  Surveying,  Levelling,  and  Setting-out;  and  in  Route 
Surveys  of  Travellers  by  Land  and  Sea.  With  Tables,  Ilhistrationg, 
and  Records.  By  L.  D'A.  JACKSON,  A.M.Inst.C.E.  Second  Edition. 
8vo,  cloth $5.00 

LAND   AND    MARINE    SURVEYING. 

In  Reference  to  the  Preparation  of  Plans  for  Roads  and  Railways; 
Canals,  Rivers,  Towns'  Water  Supplies;  Docks  and  Harbours.  With 
Description  an  dUse  of  Surveying  I  nstruu.ents.  By  W.  DAVIS  HASKOI.T., 
C.E.  Second  Edition,  Re  vised  with  Additions.  CrownSvo.cloth. 

$3.50 


CIVIL  ENGINEERING,  SURVEYING,  &c.  15 

ENGINEER'S  &   MINING   SURVEYOR'S  FIELD  BOOK. 

Consisting  of  a  Series  of  Tables,  with  Rules,  Explanation*  of  Systems 
and  use  of  Theodolite  f</r  Traverse  Surveying  and  plotting  the  work 
with  minute  arcuracv  by  means  of  Straight  Edge  and  Set  Square  only; 
I/evellinR  with  the  Theodolite,  Setting-out  Curves  with  and  without  the 
Theodolite.  Earthwork  Tables,  Ac.  By  W.  DAVIS  HASKOLL.  C.E.  With 
numerous  Woodcut*.  Fifth  Edition,  Enlarge*!.  12mo,  cloth.g4.5Q 
"The  book  is  very  hardy;  the  separate  tables  of  sines  and  tangents  to 

every  minute   wilj   make   it  useful   for  many  other  purposes,  the   genuine 

tiaverse  tables  existing  all  the  same." 

AN    OUTLINE    OF    THE    METHOD    OF    CONDUCTING 
A  TRIGONOMETRICAL  SURVEY. 

For  the  Formation  of  Geographical  and  Topographical  Maps  and  Plans, 
Military  Reconnaissance.  LEVELLING,  Ac.,  with  Useful  Problems, 
Formulsp,  and  Table?.  By  Lieut  .-General  FROME.  R.E.  1-ourth  Edi- 
tion, Revised  and  partly  Re-written  by  Major-General  Sir  CM  A  in. KM 
WARREN,  G.C.M.G.,  R.E.  With  19  Plates  and  115  Woodcuts.  Svo. 
cloth...  Stf.OU 

PRINCIPLES   AND    PRACTICE   OF    LEVELLING. 

Showing  it*  Application  to  Purpose.*"  of  Railway  and  Cm  I  Engineering 
in  the  Construction  of  Roads;  with  Mr.  TEI.FORD'S  Rules  for  the  sirne. 
By  FREDERICK  W.  SIMMS.  M.Inst.C.E.     Eighth  Edition,  with   LAW'S 
Practical  Examples  for  Setting-out  Railway  Curve*,  and  TRAPTWINK'S 
Field  Practice  of  Laying  out  Circular  Curve*.     With  7  Plates  and  nu- 
merous Woodcuts.     8vo.  .  S'*.."»U 
"The  text-book  on  levelling  in  most  of  our  engineering  schools  and  col- 
leges. "--Engineer. 

"The  publishers  have  rendered  a  substantial  service  to  the  profession, 
especially  to  the  younger  members,  by  bringing  out  the  present  edition  of 
Mr.  Simm's  useful  work." — Engineering. 

TABLES  OF  TANGENTIAL  ANGLES  AND  MULTIPLES. 

For  Setting-out  Curves  from  5  to  200  Radius.  By  A.  B'AZELEY.M.Inst. 
C.E.  7th  Edition.  Revised.  With  an  Appendix  on  the  us*  of  the 
Tables  for  Measuring  ur>  Curve*.  Printed  on  50  Cards,  and  sold  in  a 
cloth  box,  waistcoat-pocket  si«e. .  .  SI  ..">(> 

"Each  table  is  printed  on  a  small  card,  which,  placed  on  the  theodolite, 

leaves  the  hands  free  to  manipulate  the  instrument — no  small  advantage 

as  regards  the  rapidity  of  work." 

"Very  handy;  a  man  may  know  that  all  his  day's  work  must  fall  on  two 

of  these  cards,  which  be  puts  into  his  own  card-case,  and  leaves  the  rest 

behind." 

PIONEER    ENGINEERING. 

A  treatise  on  the  Engineering  Operations  connected  with  the  Settle- 
ment of  Waste  Lands  in  New  Countries.  By  E.  DOBSON,  M.Inst.C.E. 
Second  Edition.  12mo,  cloth.  .  .  SI  .SO 

"Mr.  Dobson  is  familiar  with  the  difficulties  which  have  to  be  overcome 

in  this  class  of  work,  and  much  of  his  advice  will  be  valuable  to  young 

engineers  proceeding  to  our  colonies." — Engineering. 

TUNNELLING. 

A  Practical  Treatise.  By  CHARLES  PRELINI,  C.E  With  additions  by 
CHARLKS  S.  HILL,  C.E.  With  150  Diagrams  and  Illustrations.  Royal 
8vo,  cloth. .  .  83.0O 

PRACTICAL   TUNNELLING. 

Explaining  in  detail  Setting-out  'he  Work*.  Shaft-sinking,  and  Heading- 
driving,  Ranging  the  Lines  and  Levelling  underground,  Sub-Excavat- 
ing Timbering  and  the  Construction  of  the  Brickwork  of  Tunnels.  By 
F.  W.  SIMM-  M.In<t.C.E.  Fourth  Edition.  Revised  and  Further  Ex- 
tended including  the  most  recent  (1895)  Examples  of  Sub-aqueous  and 
other  Tunnels,  by  D  KINNEAR  CLARK,  M  Inst.C.E  With  34  Folding 
Plates  Imperial  8vo,  cloth $9.00 


16        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
EARTH    AND    ROCK    EXCAVATION. 

A  Practical  Treatise,  by  CHARLES  PRELINI,  C.E.  365  pp.,  with  Tables, 
many  Diagrams  and  Engravings.  Royal  8vo,  cloth. 

[Just  Published.     $3.00 

CONSTRUCTION  OF  ROADS  AND  STREETS. 

By  H.  LAW,  C.E.,  and  D.  K.  CLARK,  C.E.  Sixth  Edition,  revised,  with 
Additional  Chapters  by  A.  J.  WALLIS-TAYLER,  A.M.Inst.C.E.  12mo, 
doth $2.50 

TRAMWAYS:  THEIR  CONSTRUCTION  AND  WORKING. 

Embracing  a  Comprehensive  History  of  the  System ;  with  an  exhaustive 
Analysis  of  the  Various  Modes  of  Traction,  including  Horse  Power, 
Steam.  Cable  Traction,  Electric  Traction,  <fcc.;  a  Description  of  the 
Varieties  of  Rolling  Stock;  and  ample  Details  of  Cost  and  Working 
Expenses.  New  Edition,  Thoroughly  Revised,  and  Including  the 
Progress  recently  made  in  Tramway  Construction,  &c.,  &c.  By  D. 
KINNEAR  CLARK,  M.lnst.C.E.  With  400  Illustrations.  8vo,  780  pp., 
buckram $7.50 

HANDY    GENERAL    EARTH-WORK   TABLES. 

Giving  the  Contents  in  Cubic  Yards  of  Centre  and  Slopes  of  Cuttings 
and  Embankments  from  3  inches  to  80  feet  in  Depth  or  Height,  for  use 
with  either  66  feet  Chain  or  100  feet  Chain.  By  J.  H.  WATSON  BUCK, 
M.lnst.C.E.  On  a  sheet  mounted  in  cloth  case $1.50 

EARTHWORK    TABLES. 

Showing  the  Contents  in  Cubic  Yards  of  Embankments.  Cuttings,  <fec., 
of  Heights  or  Depths  up  to  an  average  of  80  feet.  By  JOSEPH  BROAD- 
BENT,  C.E.,  and  FRANCIS  CAMPIN,  C.E.  12mo,  cloth $2.00 

"The  way  in  which  accuracy  is  attained,  by  a  simple  division  of  each  cross 

section  into  three  elements,  two  111  which  are  constant  and  one  variable,  is 

ingenious." 

A    MANUAL   ON    EARTHWORK. 

By  ALEX.  J.  GRAHAM,  C.E.  With  numerous  Diagrams.  Second  Edi- 
tion. 18mo,  cloth $1.00 

THE  CONSTRUCTION  OF  LARGE  TUNNEL  SHAFTS. 

A  Practical  and  Theoretical  Essay.  By  J.  H.  WATSON  BUCK,  M.Inst. 
C.E.,  Resident  Engineer,  L.  and  N.  W.  R.  With  Folding  Plates,  8vo, 

doth $4.80 

"Many  of  the  methods  given  are  of  extreme  practical  value  to  the  mason, 
and  the  observations  on  the  form  of  arch,  the  rules  for  ordering  the  stone, 
and  the  construction  of  the  templates,  will  be  found  of  considerable  use." 

ESSAY    ON    OBLIQUE    BRIDGES 

(Practical  and  Theoretical. )  With  13  large  Plates.  By  the  late  GEORGE 
WATSON  BUCK,  M.lnst.C.E  Fourth  Edition,  revised  by  his  Son,  J,  H. 
WATSON  BUCK,  M.Inst  C.E  ;  and  with  the  addition  of  Description  to 
Diagrams  for  Facilitating  the  Construction  of  Oblique  Bridges,  by  W. 
H.  BARLOW,  M.lnst.C.E  Royal  8vo,  cloth •. $4.80 

CAST    &    WROUGHT    IRON    BRIDGE   CONSTRUCTION 

(A  Complete  and  Practical  Treatise  on),  including  Iron  Foundations. 
In  Three  Parts. — Theoretical,  Practical,  and  Descriptive  By  WIL- 
LIAM HUMBER,  A.M.Inst.C.E  .  and  M  Inst.M.E.  Third  Edition. 're vised 
and  much  improved,  with  115  Double  Plates  (20  of  which  now  first 
appear  in  this  edition  ),  and  numerous  Additions  to  the  Text.  In  2  vols.. 
imp.  4to,  half-bound  in  morocco $50.00 

IRON    BRIDGES    OF    MODERATE    SPAN: 

Their  Construction  and  Erection  By  H.  W.  PENDRED  With  40  Il- 
lustrations. 12mo,  cloth 


CIVIL  ENGINEERING,  SURVEYING,  &c.  17 

IRON    AND    STEEL   BRIDGES   AND    VIADUCTS. 

A  Practical  Treatise  upon  their  Construction.  For  the  use  of  Engi- 
neers, Draughtsmen,  and  Students.  By  FRANCIS  CAMPIN,  C.E.  12mo, 

81.40 

TUBULAR    AND    OTHER    IRON    GIRDER    BRIDGES, 

Describing  the  Britannia  and  Conway  Tubular  Bridge*.  With  a 
Sketch  of  Iron  Bridges,  <fec.  By  G.  D.  DEMPHEY,  C.E.  12mo,  cloth, 

.HO 

GRAPHIC   AND    ANALYTIC   STATICS. 

In  Their  Practical  Application  to  the  Treatment  of  Stresses  in  Roofs, 
Solid  Girders,  Lattice,  Bowstring,  and  Suspension  Bridges,  Braced 
Iron  Arches  and  Piers,  and  other  Frameworks.  By  H.  HUDSON 
GRAHAM,  C.E.  Containing  Diagrams  and  Plates  to  Scale.  With  num- 
erous Examples,  many  taken  from  existing  Structures.  Socially 
arranged  for  Clans-work  .in  Colleges  and  Universities.  Second  Edition, 
Revised  and  Enlarged.  8vo,  cloth  .........................  8G.OO 

WEIGHTS  OF  WROUGHT   IRON   &   STEEL  GIRDERS. 

A  Graphic  Table  for  Facilitating  the  Computation  of  the  Weights  of 
Wrought  Iron  and  Steel  Girders,  «kc.,  for  Parliamentary  and  other 
Estimates.  By  J.  H.  WATSON  BUCK,  M.Inst.C.E.  On  a  sheet.  81.  OO 

GEOMETRY    FOR   TECHNICAL    STUDENTS. 

An  Introduction  to  Pure  and  Applied  Geometry  and  the  Mensuration 
of  Surfaces  and  Solids,  including  Problems  in  Plane  Geometry  useful  in 
Drawing.  By  E.  H.  SPRAGUE,  A.  M.Inst.C.E.  12mo,  cloth.  .  .  .50 

PRACTICAL   GEOMETRY. 

For  the  Architect,  Engineer,  and  Mechanic.    Giving  Rules  for  the  Delin- 
eation and   Application  of  various  Geometrical   Lines,   Figures,  and 
Curves.     By  E.  W.  TARN,  M.A.,  Architect.     8vo.  cloth  .......  $.'*."><> 

"No  book  with  the  same  objects  in  view  has  ever  been  published  in  which 

the  clearness  of  the  rules  laid  down  and  the  illustrative  diagrams  have  been 

BO  satisfactory."  —  Scotsman. 

THE   GEOMETRY   OF   COMPASSES. 

Or,  Problems  Resolved  by  the  mere  Description  of  Circles  and  the  Use 
of  Coloured  Diagrams  and  Symbols.  By  OLIVER  BYRNE.  Coloured 
Plates.  12mo,  cloth.  .  .  ........  81.50 


MENSURATION    AND    MEASURING. 

With  the  Mensuration  and  Levelling  of  Land  for  the  purposes  of  Modern 
Engineering.  By  T.  BAKER,  C.E.  New  Edition  by  E.  NUGENT,  C.E. 
12mo,  cloth  .......................  ..............  (JO 


HANDY   BOOK  FOR  THE  CALCULATION  OF  STRAINS 

In  Girders  and  Similar  Structures  and  their  Strength.  Consisting  of 
Formulae  and  Corresponding  Diagrams,  with  numerous  details  for  Prac- 
tical Application,  <fec.  By  WILLIAM  HTMHKR,  A.  M.Inst.C.E.,  <tc.  Sixth 
Edition.  12mo,  with  nearly  100  Woodcuts  and  3  Plates,  cloth.  82,50 

THE   STRAINS   ON    STRUCTURES   OF    IRONWORK. 

With  Practical  Remarks  on  Iron  Construction.  By  F.  W.  SHIELDS, 
M.Inst.C.E.  8vo,  cloth.  .  .  .........  82.  OO 

CONSTRUCTIONAL    IRON    AND    STEEL   WORK, 

As  applied  to  Public,  Private,  and  Domestic  Buildings.  By  FRANCIS 
CAMPIN,  C.E.  12mo,  cloth  ............................  *  .  .  -81.4O 


i8       CROSBY  LOCKWOOD  6-  SON'S  CATALOGUE. 
MATERIALS   AND    CONSTRUCTION. 

A  Theoretical  and  Practical  Treatise  on  the  Strains,  Designing,  and 
Erection  of  Works  of  Construction.  By  FRANCIS  CAMPIN,  C.E.  Third 

Edition.  12mo,  cloth SI. 20 

"No  better  exposition  of  the  practical  application  of  the  principles  of 

construction  has  yet  been  published  to  our  knowledge  in  such  a  cheap 

comprehensive  form." — Building  News. 

EXPERIMENTS   ON    THE    FLEXURE    OF    BEAMS. 

Resulting  in  the  Discoyery  of  New  Laws  of  Failure  by  Buckling.  By 
ALBERT  E.  GUY.  Medium  8vo,  cloth Net  $1.25 

TRUSSES   OF   WOOD    AND    IRON. 

Practical  Applications  of  Science  in  Determining  the  Stresses,  Breaking 
Weights,  Safe  Loads,  Scantlings,  and  Details  of  Construction.  With 
Complete  Working  Drawings.  By  W.  GRIFFITHS,  Surveyor.  Oblong, 

8vo,  cloth.  ..  $1.80 

^'This  handy  little  book  enters  so  minutely  into  every  detail  connected 

with  the  construction  of.  roof  trusses  that  no  student  need  be  ignorant  of 

these  matters." — Practical  Engineer. 

CONSTRUCTION  OF  ROOFS,  OF  WOOD  AND  IRON: 

Deduced  chiefly  from  the  Works  of  Robison,  Tredgold,  and  H  umber. 

ByE.W.  TARN,  M.A.,  Architect.  Fourth  Edition.  12mo,  cloth.  ,gQ 
"Mr.  Tarn  is  so  thoroughly  master  of  his  subject,  that  although  the  trea- 
tise was  founded  on  the  works  of  others  he  has  given  it  a  distinct  value  of 
his  own.  It  will  be  found  valuable  by  all  students." — Builder. 

A   TREATISE    ON    THE    STRENGTH   OF  MATERIALS. 

With  Rules  for  Application  in  Architecture,  the  Construction  of  Sus- 
pension Bridges,  Railways,  &c.  By  PETER  BARLOW,  F.R.S.  A  new 
Edition,  revised  by  his  Sons,  P.  W.  BARLOW,  F.R.S. ,  and  W.  H.  BARLOW. 
F.R.S. ;  to  which  are  added,  Experiments  by  HODGKINSON,  FAIRBAIRN, 
and  KIRKALDY;  and  Formulae  for  calculating  Girders,  &c.  Edited  by 
WM.  HUMBER,  A.M.Inst.C.E.  8vo,  400  pp.,  with  19  Plates  and  numer- 
ous Woodcuts,  cloth $7.0O 

"Valuable  alike  to  the  student,  tyro,  and  the  experienced  practitioner,  it 

will  always  rank  in  future  as  it  has  hitherto  done,  as  the  standard  treatise 

on  that  particular  subject." — Engineer. 

EXPANSION    OF   STRUCTURES    BY    HEAT. 

By  JOHN  KEILY,  C.E.,  late  of  the  Indian  Public  Works  Department. 

12mo,  cloth $1.50 

"The  aim  the  author  has  set  before  him,  viz.,  to  show  the  effects  of  heat 
upon  metallic  and  other  structures,  is  a  laudable  one,  for  this  is  a  branch  of 
physics  upon  which  the  engineer  or  architect  can  find  but  little  reliable  and 
comprehensive  data  in  books." — Builder. 

CIVIL    ENGINEERING. 

By  HENRY  LAW,  M.Inst.C.E.  Including  a  Treatise  on  Hydraulic  En- 
gineering by  G.  R.  BURNELL,  M.Inst.C.E.  Seventh  Edition,  re-vised, 
with  Large  Additions  on  Recent  Practice  by  D.  KINNEAR  CLARK, 
M.Inst.C.E.  12mo,  cloth $2.60 

GAS   WORKS, 

Their  Construction  and  Arrangement,  and  the  Manufacture  and  Distri- 
bution of  Coal  Gas.  By  S.  HUGHES,  C.E.  Ninth  Edition.  Revised, 
with  Notices  of  Recent  Improvements  by  HENRY  O'CONNOR,  A.M.Inst. 

C.E.     12mo,  cloth $2.40 

"Of  infinite  service  alike  to  manufacturers,  distributors,  and  consumers." 


MARINE  ENGINEERING,  NAVIGATION,  &c.        19 
PNEUMATICS, 

Including  Acoustics  and  the  Phenomena  of  Wind  Currents,  for  the  ui«e 
of  Beginners.  By  CHARLES  TOMLINSON,  F.R.S.  12mo,  cloth.  .(JO 

FOUNDATIONS    AND   CONCRETE    WORKS. 

With  Practical  Ilemarks  on  Footings,  Planking,  Sand.  Concrete,  Bit  on. 
Pile-driving,  Caissons,  and  Cofferdams.  By  E.  DOBSON.  llimo.  ^(JQ 

BLASTING    AND    QUARRYING    OF    STONE, 

For  Building  and  other  Purposes.  With  Remarks  on  the  Blowing  up  of 
Bridges.  By  Gen.  Sir  J.  BLRGOYNE,  K.C.B.  12mo,  cloth  .  tft/Q 

SAFE    RAILWAY    WORKING. 

A  Treatise  on  Railway  Accidents,  their  Cause  and  Prevention;  with  a 
Description  of  Modern  Appliances  and  Systems.  By  CLEMENT  E. 

STRKTTON,  C.E.  Third  Edition,  Enlarged.  12mo,  cloth 91. .V) 

"A  book  for  the  engineer,  the  directors,  the  managers;  and.  in  short,  all 

who  wish  for  information  on  railway  matters  will  find  a  perfect  encyclopaedia 

In  'Safe  Railway  Working.'" — Railway  Review. 


MARINE  ENGINEERING,  SHIPBUILDING, 
NAVIGATION,   ETC. 


MARINE    ENGINES   AND    BOILERS. 

Their  Design  and  Construction.  A  Handbook  for  the  Use  of  Students, 
Engineers,  and  Naval  Const  rue  tors.  Based  on  the  Work  "Berechnung 
und  Konstruktion  der  Schiffsmaschinen  und  Kessel,"  by  Dr.  d.  BAUER. 
Engineer-in-Chief  of  the  Vulcan  Shipbuilding  Yard,  Stettin.  Translated 
from  the  Second  German  Edition  by  E.  M.  DONKIN,  ami  S.  BRYAN 
DONKIN,  A.M.I.C.E.  Edited  by  LESLIE  S.  ROBERTSON,  Secretary  to 
the  Engineering  Standards  Committee,  M.I.C.E.,  M.I.M.E.,  M.I.N.A., 
&c.  With  numerous  Illustrations  and  Tables.  Thick  8vo,  cloth, 

(Just  Publithed.     89.00 

SUMMARY  OF  CONTENTS:— PART  I.— MAIN  ENGINES.— DETERMINA- 
TION OF  CYLINDER  DIMENSIONS. — THE  UTILISATION  OF  STEAM  IN  THE  EN- 
GINE.— STROKE  OF  PISTON. — NUMBER  OF  REVOLUTIONS. — TURNINO  MOMENT. 
— BALANCING  OF  THE  MOVING  PARTS. — ARRANGEMENT  OF  MAIN  ENGINES. — 
DETAILS  OF  MAIN  ENGINES. — THE  CYLINDER. — VALVES. — VARIOUS  KINDS 
OF  VALVE  GEAR. — PISTON  RODS. — PISTONS. — CONNECTING  ROD  AND  CROSS- 
HEAD. — VALVE  GEAR  RODS. — BED  PLATES. — ENGINE  COLUMNS. — REVERS- 
ING AND  TURNING  GEAR.  PART  II. — PUMPS. — AIR,  CIRCULATING  FEED, 
AND  AUXILIARY  PUMPS.  PART  III.— SHAFTING.  RESISTANCE  OF 
SHIPS,  PROPELLERS.— THRUST  SHAFT  AND  THRUST  BLOCK.— TUNNEL- 
SHAFTS  AND  PLUMMER  BLOCKS. — SHAFT  COUPLINGS. — STERN  TUBE. — THE 
SCREW  PROPELLER. — CONSTRUCTION  OF  THE  SCREW.  PART  IV. — PIPES 
AND  CONNECTIONS. — GENERAL  REMARKS,  FLANGES.  VALVES.  <fec.— 
UNDER  WATER  FITTINGS. — MAIN  STEAM,  AUXILIARY  STEAM.  AND  EXHAUST 
PIPING. — FEED  WATER.  BILGE.  BALLAST  AND  CIRCTTLATING  PIPES.  PART 
V. — STEAM  BOILERS. — FIRING  AND  THE  GENERATION  OF  STEAM. — 
CYLINDRICAL  BOILERS. — LOCOMOTIVE  BOILERS. — WATER-TUBE  BOILERS. — 
SMALL  TUBE  WATER-TUBE  BOILERS. — SMOKE  Box. — FUNNEL  AND  BOILER 
LAGGING.  —  FORCED  DRAUGHT.  —  BOILER  FITTINGS  AND  MOUNTINGS. 
PART  VI.— MEASURING  INSTRUMENTS.  PART  VII.— VARIOUS 
DETAILS. — BOLTS,  NUTS,  SCREW  THREADS.  <fec. — PLATFORMS,  GRATINGS. 
LADDERS. — FOUNDATIONS. — SEATINGB. — LUBRICATION.  —  VENTILATION  or 
ENGINE  ROOMS.— RULES  FOR  SPARE  GEAR.  PART  VIII.— ADDITIONAL 
TABLES. 


20        CROSBY  LOCKWOOD  6»  SON'S  CATALOGUE. 
THE     NAVAL     ARCHITECT'S     AND     SHIPBUILDER'S 

POCKET-BOOK 

Of  Formulae,  Rules,  and  Tables,  and  Marine  Engineer's  and  Surveyor's 
Handy  Book  of  Reference.  By  CLEMENT  MACKROW,  M.I.N.A.  Eighth 
Edition,  carefully  Revised  and  Enlarged.  Fcap,  leather.  .  Net  $5.00 
SUMMARY  OF  CONTENTS: — SIGNS  AND  SYMBOLS,  DECIMAL  FRACTIONS. — 
TRIGONOMETRY. — PRACTICAL  GEOMETRY. — MENSURATION. — CENTRES  AND 
MOMENTS  OF  FIGURES. — MOMENTS  OF  INERTIA  AND  RADII  GYRATION. — AL- 
GEBRAICAL EXPRESSIONS  FOR  SIMPSON'S  RULES. — MECHANICAL  PRINCIPLES. 
— CENTRE  OF  GRAVITY. — LAWS  OF  MOTION. — DISPLACEMENT,  CENTRE  OF 
BUOYANCY. — CENTRE  OF  GRAVITY  OF  SHIPS'  HULL. — STABILITY  CURVES  AND 
METACENTRES. — SEA  AND  SHALLOW-WATER  WAVES. — ROLLING  OF  SHIPS. — 
PROPULSION  AND  RESISTANCE  OF  VESSELS. — SPEED  TRIALS. — SAILING,  CEN- 
TRE OF  EFFORT. — DISTANCES  DOWN  RIVERS,  COAST  LINES. — STEERING  AND 
RUDDERS  OF  VESSELS. — LAUNCHING  CALCULATIONS  AND  VELOCITIES. — 
WEIGHT  OF  MATERIAL  AND  GEAR. — GUN  PARTICULARS  AND  WEIGHT. — 
STANDARD  GAUGES. — RIVETED  JOINTS  AND  RIVETING. — STRENGTH  AND 
TESTS  OF  MATERIALS. — BINDING  AND  SHEARING  STRESSES. — STRENGTH  OF 
SHAFTING,  PILLARS,  WHEELS,  «fec. — HYDRAULIC  DATA,  &c. — CONIC  SEC- 
TIONS, CATENARIAN  CURVES. — MECHANICAL  POWERS,  WORK. — BOARD  OF 
TRADE  REGULATIONS  FOR  BOILERS  AND  ENGINES. — BOARD  OF  TRADE  REG- 
ULATIONS FOR  SHIPS. — LLOYD'S  RULES  FOR  BOILERS. — LLOYD'S  WEIGHT  OF 
CHAINS. — LLOYD'S  SCANTLINGS  FOR  SHIPS. — DATA  OF  ENGINES  AND  VES- 
SELS.— SHIPS'  FITTINGS  AND  TESTS. — SEASONING  PRESERVING  TIMBER. — 
MEASUREMENT  OF  TIMBER. — ALLOYS,  PAINTS,  VARNISHES. — DATA  FOR  STOW- 
AGE.— ADMIRALTY  TRANSPORT  REGULATIONS. — RULES  FOR  HORSE-POWER, 
SCREW  PROPELLERS,  &c. — PERCENTAGES  FOR  BUTT  STRAPS. — PARTICULARS 
OF  YACHTS. — MASTING  AND  RIGGING. — DISTANCES  OF  FOREIGN  PORTS. — 
TONNAGE  TABLES.— VOCABULARY  OF  FRENCH  AND  ENGLISH  TERMS. — ENGLISH 
WEIGHTS  AND  MEASURES. — FOREGN  WEIGHTS  AND  MEASURES. — DECIMAL 
EQUIVALENTS. — USEFUL  NUMBERS. — CIRCULAR  MEASURES. — AREAS  OF  AND 
CIRCUMFERENCES  OF  CIRCLES. — AREAS  OF  SEGMENTS  OF  CIRCLES. — TABLES 
OF  SQUARES  AND  CUBES  AND  ROOTS  OF  NUMBERS. — -TABLES  OF  LOGARITHMS 
OF  NUMBERS. — TABLES  OF  HYBERPOLIC  LOGARITHMS. — TABLES  OF  NATURAL 
SINES,  TANGENTS. — TABLES  OP  LOGARITHMIC  SINES,  TANGENTS,  &c. 

WANNAN'S   MARINE    ENGINEER'S   GUIDE 

To  Board  of  Trade  Examinations  for  Certificates  of  Competency.  Con- 
taining all  Latest  Questions  to  Date,  with  Simple,  Clear,  and  Correct 
Solutions;  302  Elementary  Questions  with  Illustrated  Answers,  and 
Verbal  Questions  and  Answers;  complete  Set  of  Drawings  with  State- 
ments completed.  By  A.  C.  WANNAN,  C.E.,  Consulting  Engineer,  and 
E.  W.  I.  WANNAN,  M.I.M.E.,  Certificated  First  Class  Marine  Engineer. 
With  numerous  Engravings.  Fourth  Edition,  Enlarged.  500  pages. 
8vo,  cloth $4.00 

WANNAN'S   MARINE    ENGINEER'S   POCKET=BOOK. 

Containing  Latest  Board  of  Trade  Rules  and  Data  for  Marine  Engineers. 
By  A.  C.  WANNAN.  Third  Edition,  Revised,  Enlarged,  and  Brought  up 
to  Date.  Square  18mo,  with  thumb  Index,  leather $2.00 

MARINE    ENGINES   AND    STEAM    VESSELS. 

By  R.  MURRAY,  C.E.  Eighth  Edition,  thoroughly  Revised,  with  Addi- 
tions by  the  Author  and  by  GEORGE  CARLISLE,  C.E.  12mo,  cloth .  $1 .80 

ELEMENTARY   MARINE    ENGINEERING. 

A  Manual  for  Young  Marine  Engineers  and  Apprentices.  By  J.  S. 
BREWER.  12mo,  cloth .60 

CHAIN   CABLES   AND   CHAINS. 

Comprising  Sizes  and  Curves  9f  Links,  Studs,  &c.,  Iron  for  Cables  and 
Chains,  Chain  Cable  and  Chain  Making,  Forming  and  Welding  Links, 
Strength  of  Cables  and  Chains,  Certificates  for  Cables,  Marking  Cables, 
Prices  of  Chain  Cables  and  Chains,  Historical  Notes,  Acts  of  Parlia- 
ment, Statutory  Tests,  Charges  for  Testing,  List  of  Manufacturers  of 


MARINE  ENGINEERING,  NAVIGATION,  &c.        21 

Cables,  <fec.,  Ac.  By  THOMAS  W.  TRAILL.  F.E.R.N..  M.Inst.C.E.,  En- 
gineer-Surveyor-in-Chief,  Board  of  Trade,  Inspector  of  Chain  Cable  and 
Anchor  Proving  Establishments,  and  General  Superintendent,  Lloyd's 
Committee  on  Proving  Establishments.  With  numerous  Tables,  Illus- 
trations, and  Lithographic  Drawings.  Folio,  cloth..  .  815.0O 

THE    SHIPBUILDING    INDUSTRY    OF    GERMANY. 

Compiled  and  Edited  by  G.  LJEHHANN-FCLSKOWSKI.  With  Coloured 
Prints,  Art  Supplements,  and  numerous  Illustrations  throughout  the 
text.  Super-royal  4to,  cloth.  .  &4.'-iO 

SHIPS    AND    BOATS. 

By  W.  BLAND.  With  numerous  Illustrations  and  Models.  Tenth  Edi- 
tion. 12mo,  cloth.  .  ^(JQ 

SHIPS    FOR    OCEAN    AND    RIVER    SERVICE, 

Principles  of  the  Construction  of.     By  H.  A.  SOUMKRFELDT.      12mo. 

.60 
AN    ATLAS   OF    ENGRAVINGS 

To   illustrate  the   above.     Twelve   large  folding  Plates.     Royal   4to 

JM.OO 

NAVAL    ARCHITECTURE. 

An  Exposition  of  the  Elementary  Principles.  By  J.  PEAKK.  12mo 
cloth...  S1.40 

THE    ART    AND    SCIENCE   OF    SAILMAKING. 

By  SAMITEL  B.  SADLER,  Practical  Sailmaker.  late  in  the  employment  of 

Messrs.  Katsey  and  Lapthorne,  of  Cowes  and  Gosport.     Plates.     4to, 

cloth.  $5.0(1 

"This  extremely  practical  work  gives  a  complete  education  in  all  the 

branches  of  the  manufacture,  cutting  out,  roping,  seaming,  and  goring.     It 

8  copiously  illustrated,  and  forms  a  first-rate  text-book  and  guide." 

SAILS    AND    SAIL-MAKING. 

With  Draughting,  and  the  Centre  of  Effort  of  the  Sails.  Weights  and 
Sizes  of  Ropes;  Masting,  Rigging,  and  Sails  of  Steam  Vessels,  Ac.  By 
R.  KIPPING,  N. A.  12mo,  cloth..  .  gl.OO 

MASTING,   MAST-MAKING,   AND   RIGGING   OF  SHIPS. 

Also  Tables  of  Spars,  Rigging,  Blocks;  Chain,  Wire,  and  Hemp  Ropes, 
<kc.,  relative  to  every  class  of  vessels.  By  R.  KIPPING.  12mo,  cloth, 

.80 

SEA   TERMS,    PHRASES,    AND   WORDS 

(Technical  Dictionary  of)  used  in  the  English  and  French  Languages 
(English- French,  French- English).  For  the  Use  of  Seamen,  Engineers, 
Pilots,  Shipbuilders,  Shipowners,  and  Ship-brokers.  Compiled  by  W. 
PIRRIE,  late  of  the  Afncan  Steamship  Company.  Fcap,  8vo,  cloth 
limp...  32.0O 

This  volume  will  be  highly  appreciated  by  seamen,  engineers,  pilots,  ship- 
builders and  shipowners.  It  will  be  found  wonderfully  accurate  and  com- 
plete. 

SAILOR'S   SEA    BOOK: 

A  Rudimentary  Treatise  on  Navigation.  By  JAMES  GREENWOOD,  B.A. 
With  numerous  Woodcuts  and  Coloured  Plates.  New  and  Enlarged 

Edition.     By  W.  H.  ROSSER.     12mo,  cloth. ..  81.OO 

Is  perhaps  the  best  and  simplest  epitome  of  navigation  ever  compiled. 

PRACTICAL    NAVIGATION. 

Consisting  of  the  Sailor's  Sea  Book,  by  J.  GREENWOOD  and  W.  H.  ROSSER; 
together  with  Mathematical  and  Nautical  Tables  for  the  Working  of  the 
Problems,  by  H.  LAW,  C.E.,  and  Prof.  J.  R.  YOUNG $2  8Q 


22        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
NAVIGATION    AND    NAUTICAL    ASTRONOMY, 

In  Theory  and  Practice.     By  Prof.  J.  R.  YOUNG.     12mo, 
"A  very  complete,  thorough,  and  useful  manual  for  the  young  navigator." 

MATHEMATICAL   TABLES, 

For  Trigonometrical,  Astronomical,  and  Nautical  Calculations;  to 
which  is  prefixed  a  Treatise  on  Logarithms,  by  H.  LAW,  C.E.  With 
Tables  for  Navigation  and  Nautical  Astronomy.  By  Prof.  J.  R.  YOUNG. 
12mo,  cloth $1.60 


MINING,   METALLURGY,  AND 
COLLIERY  WORKING. 


THE    OIL    FIELDS    OF    RUSSIA    AND    THE    RUSSIAN 

PETROLEUM   INDUSTRY. 

A  Practical  Handbook  on  the  Exploration,  Exploitation,  and  Manage- 
ment of  Russian  Oil  Properties,  including  Notes  on  the  Origin  of  Petro- 
leum in  Russia,  a  Description  of  the  Theory  and  Practice  of  Liquid 
Fuel,  and  a  Translation  of  the  Rules  and  Regulations  concerning  Rus- 
sian Oil  Properties.  By  A.  BEEBY  THOMPSON,  A.M.I.M.E.,  late  Chief 
Engineer  and  Manager  of  the  European  Petroleum  Company's  Russian 
Oil  Properties.  About  500  pp.  With  numerous  Illustrations  and 
Photographic  Plates,  and  a  Map  of  the  Balakhany-Saboontchy-Romany 
Oil  Field.  Royal  8vo,  cloth  ..........................  Net 


MECHANICS   OF   AIR    MACHINERY. 

By  Dr.  J.  WEISBACH  and  Prof.  G.  HERRMANN.     Authorized  Translation 
with  an  Appendix  on  American  Practice  by  A.  TROWBRIDGE,  Ph.B., 
Adjunct   Professor  of  Mechanical  Engineering,  Columbia  University. 
Royal  8vo,  cloth  .....................  [Just  Published.     Net  $3.7£> 

SUMMARY  OF  CONTENTS:  —  THE  MOVEMENT  OP  AIR.  —  NATURAL  AND  ARTI- 

FICIAL VENTILATION.  —  BLOWING-ENGINES;  —  VACUUM   PUMPS;    TUYERES; 

HOT-AIR   BLAST;    WORK   PERFORMED   BY  BLOWERS;    BLAST-RESERVOIRS; 

PISTON-BLOWERS.  —  COMPRESSORS.  —  ROTARY     BLOWERS.  —  FANS.  —  RECENT 

AMERICAN  PRACTICE,  &c. 

MACHINERY    FOR   METALLIFEROUS   MINES. 

A  Practical  Treatise  for  Mining  Engineers,  Metallurgists,  and  Managers 
of  Mines.     By  E.  HENRY  DAVIES,  M.E.,  F.G.S.     600  pp.     With  Fold- 
ing Plates  and  other  Illustrations.     Medium  8vo,  cloth  ........  $8.00 

"Deals  exhaustively  with  the  many  and  complex  details  which  go  to 
make  up  the  sum  total  of  machinery  and  other  requirements  for  the  success- 
ful working  of  metalliferous  mines,  and  as  a  book  of  ready  reference  is  of 
the  highest  value  to  mine  managers  and  directors."  —  Mining  Journal. 

THE    DEEP   LEVEL   MINES   OF  THE    RAND, 

And  their  Future  Development,  considered  from  the  Commercial  Point 
of  View.     By  G.  A.  DENNY  (of  Johannesburg),  M.N.E.I.M.E.,  Con- 
sulting Engineer  to  the  General  Mining  and  Finance  Corporation,  Ltd., 
of  London,  Berlin,  Paris,  and  Johannesburg.     Fully  Illustrated  with 
Diagrams  and  Folding  Plates.     Royal  8vo,  buckram  ........  $10.00 

"Mr.  Denny  by  confining  himself  to  the  consideration  of  the  future  of  the 
deep-level  mines  of  the  Rand  breaks  new  ground,  and  by  dealing  with  the 
subject  rather  from  a  commercial  standpoint  than  from  a  scientific  one, 
appeals  to  a  wide  circle  of  readers.  The  book  cannot  fail  to  prove  of  very 
great  value  to  investors  in  South  African  mines."  —  Mining  Journal, 


MINING,  METALLURGY,  c-  COLLIERY  WORKING.  23 
PROSPECTING  FOR  GOLD. 

A  Handbook  of  Practical  Information  and  Hints  for  Prospectors  based 

on  Personal  Experience.     By  DANIEL  J.  RANKIN.  F.R.S.O.8.,  M.R.A.S., 

formerly   Manager  of   the  Central   African   Company,   and    Leader  of 

African  Gold  Prospecting   Expeditions.      With  Illustrations  specially 

Drawn  and  Engraved  for  the  Work.      Fcap.  8vo,  leather  .$;$.OtJ 

"  This  well-compiled  book  contains  a  collection  of  the  richest  gems  of  usj- 

f.il   knowledge  for  the   prospector's   benefit.     A  special    table   is  given   to 

u  -celerate  the  spotting  at  a  glance  of  minerals  associated  with  gold." — Min- 

.ny  Journal. 

TdE    METALLURGY    OF    GOLD. 

A  Practical  Treatise  on  the  Metallurgical  Treatment  of  Gold-bearing 
Ores.      Including  the  Assaying.  Melting,  and  Refining  of  (iold.      By  M. 
EISHLKK,  M.Inst.M.M.      Fifth  Edition,  Enlarged.      With  over  300  Illus- 
trations and  numerous  Folding  Plates.      Medium  Svo.  cloth:      J$/./>() 
"This  book  thoroughly  deserves  its  title  of  a  'Practical  Treatise.'     The 
whole  process  of  gold  mining,  from  the  breaking  of  the  quartz  to  the  assay 
of  the  bullion,  is  described  in  clear  and  orderly  narrative  and  with  much 
fulness  of  detail." 

THE  CYANIDE  PROCESS  OF  GOLD  EXTRACTION, 

And  its  Practical  Application  on  the  Witwatersrand  Gold  Fields  and 
elsewhere.  By  M.  EISHLER,  M.Inst.M.M.  With  Diagrams  ami  Work- 
ing Drawings.  Third  Edition,  Revised  and  Enlarged.  8vo.  cloth. 

83.00 

"This  book  is  just  what  was  needed  to  acquaint  mining  men  with  the 
actual  working  of  a  process  which  is  not  only  the  most  popular,  but  is.  as 
a  general  rule,  the  most  successful  for  the  extraction  of  gold  from  tailings." 
— -A fining  Journal. 

DIAMOND  DRILLING  FOR  GOLD  &  OTHER  MINERALS. 

A  Practical  Handbook  on  the  Use  of  Modern  Diamond  Core  Drills  in 
Prospecting  and  Exploiting  Mineral -Bearing  Properties,  including  Par- 
ticulars of  the  Costs  of  Apparatus  and  Working.  By  G.  A.  DENNY, 
M.N.E.Inst.M.E.,  M.Inst.M.M.  Medium  8vo.  168  pp.,  with  Illustra- 
tive Diagrams.  ...  £5.O() 
"There  is  certainly  scopa  for  a  work  on  diamond  drilling,  and  Mr.  Denny 

deserves   grateful   recognition   for   supplying   a   decided    want." — Mining 

Journal. 


GOLD    ASSAYING. 

A  Practical  Handbook,  giving  the  Modu*  Operandi  for  the  Accurate 
Assay  of  Auriferous  Ores  and  Bullion,  and  the  Chemical  Tests  required 
in  the  Processes  of  Extraction  by  Amalgamation,  Cyanidation,  and 
Chlorination.  With  an  Appendix  of  Tables  and  Statistics.  By  H. 
JOSHUA  PHILLIPS,  F.I.C..  F.C.S.,  Assoc  Inst.C.E.,  Author  of  "  Engineer- 
ing Chemistry,"  &c.  With  numerous  Illustrations.  12mo,  cloth .  $3.00 

FIELD   TESTING    FOR   GOLD    AND   SILVER. 

A  Practical  Manual  for  Prospectors  and  Miners.  By  W.  H.  MERRITT 
M.N.E.Inst.M.E..  A.R.S.M.,  &c.  With  Photographic  Plates  and  other 

Illustrations.     Fcap.  8vo,  leather.  ...  si  .50 

'As  an  instructor  of  prospectors'  classes  Mr.  Merritt  has  the  advantage  of 
knowing  exactly  the  information  likely  to  be  most  valuable  to  the  miner 
in  the  field.  The  contents  cover  all  the  details  for  sampling  and  testing 
gold  and  silver  ores.  A  useful  addition  to  a  prospector's  kit." —  Mining 
Journal. 


24        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
THE    PROSPECTOR'S    HANDBOOK. 

A  Guide  for  the  Prospector  and  Traveller  in  search  of  Metal-Bearing  or 

other  Valuable  Minerals.     By  J.  W.  ANDERSON,  M.A.(Camb.),  F.R.G.S. 

Tenth  Edition.      12mo,  cloth.  .  .    $1.5O 

"How  to  find  commercial  minerals,  and  how  to  identify  them  when  they 

are  found,  are  the  leading  points  to  which  attention  is  directed." — Mining 

Journal. 

THE    METALLURGY    OF    SILVER. 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviation 
of  Silver  Ores.  Including  the  Assaying,  Melting,  and  Refining  of  Silver 
Bullion.  By  M.  EISSLER,  M.Inst.M.M.  Fifth  Edition.  12mo,  cloth. 

$4.00 

"A  practical  treatise  and  a  technical  work  which  we  are  convinced  will 
supply  a  long-felt  want  amongst  practical  men,  and  at  the  same  time  be  of 
value  to  students  and  others  indirectly  connected  with  the  industries." — 
Mining  Journal. 

THE    HYDRO=METALLURGY    OF   COPPER. 

Being  an  Account  of  Processes  Adopted  in  the  Hydro-Metallurgical 
Treatment  of  Cupriferous  Ores,  Including  the  Manufacture  of  Copper 
Vitriol,  with  Chapters  on  the  Sources  of  Supply  of  Copper  and  the 
Roasting  of  Copper  Ores.  By  M.  EISSLER,  M.Inst.M.M.  8vo,  cloth, 

$4.50 

"In  this  volume  the  various  processes  for  the  extraction  of  copper  by  wet 
methods  are  fully  detailed.  Costs  are  given  when  available,  and  a  great 
deal  of  useful  information  about  the  copper  industry  of  the  world  is  pre- 
sented in  an  interesting  and  attractive  manner." — Mining  Journal. 

THE    METALLURGY    OF    ARGENTIFEROUS    LEAD. 

A  Practical  Treatise  on  the  Smelting  of  Silver-Lead  Ores  and  the  Refin- 
ing of  Lead  Bullion.  Including  Reports  on  various  Smelting  Estab- 
lishments and  Descriptions  of  Modern  Smelting  Furnaces  and  Plants 
in  Europe  and  America.  By  M.  EISSLER,  M.Inst.M.M.  12mo,  cloth 

$5.00 

"The  numerous  metallurgical  processes,  which  are  fully  and  extensively 
treated  of,  embrace  all  the  stages  experienced  in  the  passage  of  the  lead 
from  the  various  natural  states  to  its  issue  from  the  refinery  as  an  article 
of  commerce." — Practical  Engineer. 

METALLIFEROUS    MINERALS   AND    MINING. 

By  D.  C.  DAVIER,  F.G.S.  Sixth  Edition,  thoroughly  Revised  and  much 
Enlarged  by  his  Son,  E.  HENRY  DA  VIES,  M.E.,  F.G.S.  600  pp.,  with 

173  Illustrations.     8vo,  cloth Net  $5.00 

"Neither  the  practical  miner  nor  the  general  reader,  interested  in  mines, 
can  have  a  better  book  for  his  companion  and  his  guide." — Mining  Journal. 

EARTHY  AND  OTHER  MINERALS  AND  MINING. 

By  D.  C.  DAVIES,  F.G.S.,  Author  of  "Metalliferous  Minerals,"  &c. 
Third  Edition,  Revised  and  Enlarged  by  his  Son,  E.  HENRY  DAVIES, 
M.E.,  F.G.S.  With  about  100  Illustrations.  12mo,  cloth.  .  .  .$5.00 

BRITISH    MINING. 

A  Treatise  on  the  History,  Discovery,  Practical  Development,  and 
Future  Prospects  of  Metalliferous  Mines  in  the  United  Kingdom.  By 
ROBERT  HUNT,  F  R.S.,  late  Keeper  of  Mining  Records.  Upwards  of 
950  pp.,  with  230  Illustrations.  Second  Edition,  Revised.  Super-royal 
8vo,  cloth $15.0O 

POCKET=BOOK  FOR  MINERS  AND  METALLURGISTS. 

Comprising  Rules,  Formulae,  Tables,  and  Notes  for  Use  in  Field  and 
Office  Work.  By  F.  DANVERS  POWER,  F.G.S.,  M.E.  Second  Edition, 
Corrected.  Fcap.  8vo,  leather $3.50 


MINING,  METALLURGY,  &  COLLIERY  WORKING.  25 
THE  MINER'S  HANDBOOK. 

A  Handy  Book  of  Reference  on  the  subjects  of  Mineral  Deposits.  Mining 
Operations,  Ore  Dreeing,  &c.  For  the  Use  of  Students  and  others  in- 
terested in  Mining  Matters.  Compiled  by  JOHN  MILNE,  F.R.S..  Pro- 
fessor of  Mining  in  the  lmj>erial  University  of  Japan.  Third  Edition. 
Fcap.  8vo,  leather..  .  .  $;{.OO 

IRON    ORES   of   GREAT    BRITAIN    and    IRELAND. 

Their  Mode  of  Occurrence,  Age  and  Origin,  and  the  Methods  of  Searching 
for  and  Working  Them.  With  a  Notice  of  some  of  the  Iron  Ores  of 
Spain.  By  J.  D.  KENDALL,  F.G.S.,  Mining  Engineer.  12mo,  cloth 

84UM) 
METALLURGY    OF    IRON. 

Containing  History  of  Iron  Manufacture.  Methods  of  Assay,  and  Analy- 
ses of  Iron  Ores,  Processes  of  Manufacture  of  Iron  and  Steel,  Ac.      By 
H.  BAUERMAN.  F.G.S.,  A.K.S.M.     With  numerous  Illustrations.    Sixth 
.     Edition,  revised  ami  enlarged.      12mo,  cloth .  .  S'*.OO 

"Carefully  written,  it  has  the  merit  of  brevity  and  conciseness,  as  to  leas 
important  point-*;  while  all  material  matters  are  very  fully  and  thoroughly 
entered  into." — Standard. 

MINE    DRAINAGE. 

A  Complete  Practical  Treatise  on  Direct-Acting  Underground  Steam 
Pumping  Machinery.  By  STEPHEN  MICHELL.  Second  Edition,  Re- 
written  and  Enlarged.  With  250  Illustrations.  Royal  8vo,  cloth. 

810.00 

HORIZONTAL  PUMPING  ENGINES.-RoTART  AND  NON-ROTARY 
HORIZONTAL  ENGINES. — SIMPLE  AND  COMPOUND  STEAM  PUMPS. — VERTI- 
CAL PUMPING  ENGINES.— ROTARY  AND  NON-ROTARY  VERTICAL 
ENGINES. — SIMPLE  AND  COMPOUND  STEAM  PUMPS. — TRIPLE-EXPANSION 
STEAM  PUMPS. — PULSATING  STEAM  PUMPS. — PUMP  VALVES. — SINKING 
PUMPS,  &c.,  Ac. 

ELECTRICITY   AS   APPLIED   TO   MINING. 

ByARNOLD  LUPTON,  M.Iiwt.C.E..  M.I.M.E.,  M.I.E.E..  late  Professor  of 
Coal  Mining  at  the  Yorkshire  College.  Victoria  University,  Mining  En- 

B'neer  and  Colliery  Manager;  G.  D.  ABPINALL  PARR.  M.I.E.E..  A.M.I. 
.E.,  Associate  of  the  Central  Technical  College,  City  and  Guilds  of 
London,  Head  of  the  Electrical  Engineering  Department,  Yorkshire 
College.  Victoria  University;  and  HERBERT  PERKIN,  M.I.M.E.,  Certifi- 
cated Colliery  Manager,  Assistant  Lecturer  in  the  Mining  Department  of 
the  Yorkshire  College,  Victoria  University.  With  about  170  Illustra- 
tions. Second  Edition,  Revised  and  Enlarged.  Medium  8vo,  cloth. 

[Just  Publithed.}      S4.5O 
(For  SUMMARY  or  CONTENTS,  see  page  28.) 

THE   COLLIERY    MANAGER'S   HANDBOOK. 

A  Comprehensive  Treatise  on  the  Laying-out  and  Working  of  Collieries, 
Designed  as  a  Book  of  Reference  for  Colliery  Managers,  and  for  the 
Use  of  Coal-Mining  Students  preparing  for  First-class  Certificates.     By 
CALEB  PAMELY.  Mining  Engineer  and  Surveyor;   Member  of  the  North 
of  England  Institute  of  Mining  and  Mechanical  Engineers;  and  Member 
of  the  South  Wales  Institute  of  Mining  Engineers.     With  over  1.000 
Diagrams,   Plans,   and   other  Illustrations.     Fifth    Edition,   Carefully 
Revised  and  Greatly  Enlarged.    1.200  pp.    Medium  8vo,  cloth. glQ.OO 
GBOLOOY. — SEARCH  FOR  COAL.- -MINERAL  LEASES  AND  OTHER  HOLDINGS. — 
SHAFT  SINKING. — FITTING  UP  THE  SHAFT  AND  SURFACE  ARRANGEMENTS. — 
STEAM  BOILERS  AND  THEIR  FITTINGS. — TIMBERING  AND  WALLING. — NARROW 
WORK  AND  METHODS  OF  WORKING. — UNDERGROUND  CONVEYANCE. — DRAIN- 
AGE.— THE  GAAKR  MET  WITH  IN  MINES;  VENTILATION. — ON  THE  FRICTION  OF 
AIR  IN  MINES. — THE  PRIESTMAN  OIL  ENGINE;    PETROLEUM  AND  NATURAL 
GAS. — SURVEYING  AND  PLANNING. — SAFETY  L\MPS  AND  FIREDAMP  DETECT- 
ORS.— SUNDRY  AND  INCIDENTAL  OPERATIONS  AND  APPLIANCES. — COLLIERY 
EXPLOSIONS.  —  MISCELLANEOUS   QUESTIONS    AND    ANSWERS.  —  Appendix: 
SUMMARY  OF  REPORT  or  H.M.  COMMISSIONERS  ON  ACCIDENTS  IN  MINES. 


26        CROSBY  LOCKWOOD  6*  SON'S  CATALOGUE. 
PRACTICAL   COAL=MINING. 

An  Elementary  Class-Book  for  the  Use  of  Students  attending  Classes  in 
Preparation  tor  the  Board  of  Education  and  County  Council  Examina- 
tions, or  Qualifying  for  First  or  Second  Class  Colliery  Managers'  Cer- 
tificates. By.  T.  H.  COCKIN,  Member  ot  the  Institution  of  Mining 
Engineers,  Certificated  Colliery  Manager,  Lecturer  on  Coal-Mining  at 
Sheffield  University  College.  With  Map  of  the  British  Coal-fields  and 
over  200  Illustrations  specially  Drawn  and  Engraved  for  the  Work. 
440  pp.,  12mo,  cloth $2.50 

COLLIERY   WORKING    AND    MANAGEMENT. 

Comprising  the  Duties  of  a  Colliery  Manager,  the  Oversight  and  Arrange- 
ment of  Labour  and  Wages,  and  the  different  Systems  of  Working  Coal 
Seams.  By  H.  F.  BULMAN  and  R.  A.  S.  REDMAYNE.  350  pp.,  with 
28  Plates  and  other  Illustrations,  including  Underground  Photographs. 
Medium  8vo,  cloth Net  §56.00 

NOTES   AND    FORMUL/E    FOR   MINING    STUDENTS. 

By  JOHN  HERMAN  MERIVALE,  M.A.,  Late  Professor  of  Mining  in  the 
Durham  College  of  Science,  Newcastle-upon-Tyne.  Fourth  Edition, 
Revised  and  Enlarged.  By  H.  F.  BULMAN,  A.M.Inst.C.E.  12mo, 

cloth.  .  .  Sl.OO 

"The  author  has  done  his  work  in  a  creditable  manner,  and  has  produced 

a  book  that  will  be  of  service  to  students  and  those  who  are  practically 

engaged  in  mining  operations." — Engineer. 

PHYSICS   AND    CHEMISTRY    OF    MINING. 

An  Elementary  Class-Book  for  the  use  of  Students  preparing  for  the 
Board  of  Education  and  County  Council  Examinations  in  Mining,  or 
Qualifying  for  Colliery  Managers'  Certificates.  By  T.  H.  BYROM, 
Chemist  to  the  Wigan  Coal  and  Iron  Co.,  Ltd.,  &c.  With  Illustrations. 
12mo,  cloth [Just  Published.]  $1.50 

MINING    CALCULATIONS. 

For  the  use  of  Students  Preparing  for  the  Examinations  for  Colliery 
Managers'  Certificates,  comprising  Numerous  Rules  and  Examples  in 
Arithmetic,  Algebra,  and  Mensuration.  By  T.  A.  O'DONAHUE,  M.E., 
First-class  Certificated  Colliery  Manager.  12mo,  cloth $1.50 

COAL   AND    COAL   MINING. 

By  the  late  Sir  WARINGTON  W.  SMYTH,  M.A.,  F.R.S.  Eighth  Edition, 
Revised  and  Extended  by  T.  FORSTER  BROWN,  Chief  Inspector  of  the 
Mines  of  the  Crown  and  of  the  Duchy  of  Cornwall.  12mo,  cloth. $1.40 

INFLAMMABLE    GAS   AND    VAPOUR    IN    THE    AIR 

(The  Detection   and   Measurement   of).     By   FRANK   CLOWES,   D.Sc., 

Lond.,  F.I.C.     With  a  Chapter  on  THE  DETECTION  AND  MEASUREMENT 

OF  PETROLEUM  VAPOUR,  by  BOVERTON  REDWOOD,  F.R.S. E.     12mo, 

cloth...  •• -&2.50 

"Professor  Clowes  has  given  us  a  volume  on  a  subject  of  much  industrial 

importance.   .   .     Those  interested  in  these  matters  may  be  recommended 

to  study  this  book,  which  is  easy  of  comprehension  and  contains  many  good 

things." — The  Engineer. 

COAL  &  IRON  INDUSTRIES  of  the  UNITED  KINGDOM. 

Comprising  a  Description  of  the  Coal  Fields  and  of  the  Principal  Seams 
of  Coal,  with  Returns  of  their  Produce  and  its  Distribution ,  and  Analyses 
of  Special  Varieties.  Also,  an  Account  of  the  Occurrence  of  Iron  Ore 
in  Veins  or  Seams;  Analyses  of  each  Variety;  and  a  History  of  the 
Rise  and  Progress  of  Pig  Iron  Manufacture.  By  RICHARD  MEADE.  8vo, 


MINING,  METALLURGY,  &  COLLIERY  WORKING.  27 
MINING    TOOLS, 

Manual  of.  By  VV.  MOROINH,  Lecturer  on  Mining  at  the  Bristol  School 
of  Mines.  12mo,  cloth..  s  |  .(id 

Atlas  of  Engravings  to  the  above,  containing  235  Illustrations  drawn 
to  Scale.  4to.  .  91. SO 

SLATE    AND    SLATE    QUARRYING. 

Scientific,  Practical,  and  Commercial.  By  D.  C.  DA  VIES,  F.G.S..  Min- 
ing Engineer,  Ac.  With  numerous  Illustration*  and  Folding  Plates 
Fourth  Edition.  12mo.  cloth.  .  81.20 

A    FIRST    BOOK    OF   MINING    AND   QUARRYING. 

By  J.  H.  COLLINS.  F.G.S.     Crown  8vo,  cloth.  .  .  ...       ,(JQ 

ASBESTOS   AND    ASBESTIC. 

Their  Properties.  Occurrence,  and  Use.  By  ROBERT  H.  JON  KB,  F.S.A. 
Mineralogist,  Hon.  Mem.  Asbestos  Club.  Black  Lake.  Canada.  With 
Ten  Collotype  Plates  and  other  Illustrations.  iJetny  8vo,  cloth.  $4>.4() 

GRANITES   AND    OUR    GRANITE    INDUSTRIES. 

By  GEORGE  F.  HARRIS,  F.G.S.    With  Illustrations.    12mo,  cloth.  81  .(H) 

MINERAL    SURVEYOR    AND    VALUER'S   GUIDE. 

Comprising  a  Treatise  on  Improved  Mining  Surveying  and  the  Valuation 
of  Mining  Properties,  with  New  Traverse  Tables.  By  W.  LINTKRN.  C.K. 

Fourth  Edition,  enlarged-      12mo,  cloth.     .  81. 4O 

"Contains  much  valuable  information,  and  is  thoroughly  trustworthy." — 
Iron  and  Coal  Trade*  Review. 

TRAVERSE   TABLES. 

For  use  in  Mine  Surveying.  By  WILLIAM  LINTERN.  C.E.  With  two 
plates.  Small  crown  8vo,  cloth.  .  ..Net  S|..~,n 

SUBTERRANEOUS    SURVEYING. 

By  T.  FENWICK.  Also  the  Method  of  Conducting  Subterraneous  Sur- 
veys without  the  use  of  the  Magnetic  Needle,  «fcc.  By  T.  BAKER.  12mo, 

81.00 
MINERALOGY, 

Rudiments  of.  By  A.  RAMSAY,  F.G.S.  Fourth  Edition.  Woodcuts 
and  Plates.  12mo,  cloth 81.40 

PHYSICAL   GEOLOGY, 

Partly  based  on  Major-General  PORTLOCK'S  "Rudiments  of  Geology." 
By  RALPH  TATE,  A.L.S.,  <fcc.  Woodcuts.  12mo,  cloth .80 

HISTORICAL   GEOLOGY, 

Partly  based  on  Major-General  PORTLOCK'S  "Rudiments."  By  RALPH 
TATE.  12mo,  cloth..  .  81.00 

GEOLOGY, 

PHYSICAL  and  HISTORICAL.  Consisting  of  "Physical  Geology,"  which 
sets  forth  the  Leading  Principles  of  the  Science:  and  "Historical  Geol- 
ogy," which  treats  of  the  Mineral  and  Organic  Conditions  of  the  Earth 
at  each  successive  epoch.  By  R.  TATE.  12mo,  cloth 81.80 


28      .  CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 


ELECTRICITY,  ELECTRICAL 
ENGINEERING,   ETC. 


THE    ELEMENTS   OF    ELECTRICAL    ENGINEERING. 

A  First  Year's  Course  for  Students.      By  TYSON  SEWELL,  A.I.E.E., 
Assistant  Lecturer  and  Demonstrator  in  Electrical  Engineering  at  the 
Polytechnic,  Regent  Street,  London.     Third  Edition,  Revised  and  En- 
larged, including  an  Appendix  of  Questions  and  Answers.     460  pages, 
with  274  Illustrations.     Demy  8vo,  cloth. .  . .  [Just  Published.]     $3.00 
OHM'S  LAW. — UNITS  EMPLOYED  IN  ELECTRICAL,   ENGINEERING. — SERIES, 
AND  PARALLEL  CIRCUITS;  CURRENT  DENSITY  AND  POTENTIAL  DROP  IN  THE. 
CIRCUIT. — THE  HEATING  EFFECT  OF  THE  ELECTRIC  CURRENT. — THE  MAG- 
NETIC EFFECT  OF  AN  ELECTRIC  CURRENT. — THE  MAGNETISATION  OF  IRON. — 
ELECTRO-CHEMISTRY;     PRIMARY    BATTERIES. — ACCUMULATORS. — INDKAT- 
ING  INSTRUMENTS;    AMMETERS,  VOLTMETERS,  OHMMETERS. — ELECTRICITY 
SUPPLY  METERS. — MEASURING  INSTRUMENTS,  AND  THE  MEASUREMENT  OF 
ELECTRICAL    RESISTANCE. — MEASUREMENT    OF    POTENTIAL    DIFFERENCE 
CAPACITY  CURRENT  STRENGTH,  AND  PERMEABILITY. — ARC  LAMPS. — INCAN- 
DESCENT LAMPS,  MANUFACTURE  AND  INSTALLATION;    PHOTOMETRY. — THE 
CONTINUOUS  CURRENT  DYNAMO. — DIRECT  CURRENT  MOTORS. — ALTERNATING 
CURRENTS. — TRANSFORMERS,  ALTERNATORS,  SYNCHRONOUS  MOTORS. — POLY- 
PHASE WORKING. — APPENDIX  OF  QUESTIONS  AND  ANSWERS. 

ELEMENTARY    ELECTRICAL    ENGINEERING 

In  Theory  and  Practice.  A  Class-book  for  Junior  and  Senior  Students 
and  Working  Electricians.  By  J.  H.  ALEXANDER,  M.B.,  A.I.E.E 
With  181  Illustrations.  12mo,  cloth [Just  Published.  $1.50 

THE    ELECTRICAL   TRANSMISSION    OF    ENERGY. 

A  Manual  for  the  Design  of  Electrical  Circuits.  By  ARTHUR  VAUGHAN 
ABBOTT,  C.E.,  Member  American  Institute  of  Electrical  Engineers, 
Member  American  Institute  of  Mining  Engineers,  Member  American 
Society  of  Civil  Engineers,  Member  American  Society  of  Mechanical 
Engineers,  &c.  With  Ten  Folding  Diagrams  and  Sixteen  Full-page 
Engravings.  Fourth  Edition,  entirely  Re- Written  and  Enlarged. 
Royal  8vo,  cloth Net  $5.00 

ELECTRICITY   AS   APPLIED   TO    MINING. 

By  ARNOLD  LUPTON,  M.Inst.C.E.,  M.I.M.E.,  M.I.E.E.,  late  Professor  of 
Coal  Mining  at  the  Yorkshire  College,  Victoria  University,  Mining  En- 
gineer and  Colliery  Manager;  G.  D.  ASPINALL  PARR,  M.I.E.E.,  A.M.I. 
M.E.,  Associate  of  the  Central  Technical  College,  City  and  Guilds  of 
London,  Head  of  the  Electrical  Engineering  Department,  Yorkshire 
College,  Victoria  University;  and  HERBERT  PERKIN,  M.I.M.E.,  Cer- 
tificated Colliery  Manager,  Assistant  Lecturer  in  the  Mining  Depart- 
ment of  the  Yorkshire  College,  Victoria  University.  With  about  170 
Illustrations.  Second  Edition,  Revised  and  Enlarged.  Medium  8vo, 

cloth [ Just  Published.     $4.5O 

INTRODUCTORY. — DYNAMIC  ELECTRICITY. — DRIVING  OF  THE  DYNAMO. — 
THE  STEAM  TURBINE. — DISTRIBUTION  OF  ELECTRICAL  ENERGY. — STARTING 
AND  STOPPING  ELECTRICAL  GENERATORS  AND  MOTORS. — ELECTRIC  CABLES. — 
CENTRAL  ELECTRICAL  PLANTS. — ELECTRICITY  APPLIED  TO  PUMPING  ANI> 
HAULING. — ELECTRICITY  APPLIED  TO  COAL-CUTTING. — TYPICAL  ELECTRIC 
PLANTS  RECENTLY  ERECTED. — ELECTRIC  LIGHTING  BY  ARC  AND  GLOW 
LAMPS. — MISCELLANEOUS  APPLICATIONS  OF  ELECTRICITY. — ELECTRICITY  AS 
COMPARED  WITH  OTHER  MODES  OF  TRANSMITTING  POWER. — DANGERS  os 
ELECTRICITY. 


ELECTRICITY,  ELECTRICAL  ENGINEERIXG,  6-c.  29 
CONDUCTORS    FOR    ELECTRICAL    DISTRIBUTION. 

Their  Materials  and  Manufacture,  The  Calculation  of  Circuits,  Pole-Line 
Construction,  Underground  Working,  and  other  Uses.  By  F.  A.  C. 
PKKRINE,  A.M.,  D.Se. ;  formerly  Professor  of  Electrical  Engineering, 
Leland  Stanford,  Jr.,  University;  M.Ainer.I.E.E.  8vo,  cloth. 

•v«  83.50 

CONDUCTOH  MATERIALS. — ALLOYED  CONDUCTORS.— MANUFACTURE  or 
WIRE. — WIRE-FINISHING. — WIRE  INSULATION  — CAHLEM. — CALCULATION  OK 
CIRCUITS. — KELVIN'S  LAW  ov  ECONOMY  IN  CONDUCTORS.-  -MULTIPLE  ARC 
DISTRIBUTION. — ALTERNATING  CURRENT  CALCULATION.  -OVERHEAD  LINES. 
— POLE  LINE. — LINE  INSULATORS. — UNDERGROUND  CONDUCTORS. 

DYNAMO    ELECTRIC    MACHINERY:     its    CONSTRUC- 
TION,  DESIGN,  and  OPERATION. 

By  SAMUEL  SHELDON,  A.M.,  Ph.D.,  Professor  of  Physics  and  Electrical 
Engineering  at  the  Polytechnic  Institute  of  Brooklyn,  assisted  by  H. 
MASON.  B.S. 

In  two  volumes,  sold  separately,  as  follows: — 

Vol.  I.— DIRECT   CURRENT    MACHINES.     Fifth  Edition.  Revised. 

8vo.     280  pages,  with  200  Illustration*  ^82.50 

Vol.11.— ALTERNATING  CURRENT  MACHINES.     8vo.     200  pages. 

with  184  Illustrations.  .  Net  82.. 5O 

Designed  as  Text-books  for  use  in  Technical  Educational  Institutions,  and 

by  Engineers  whose  work  includes  the  handling  of  Direct  and  Alternating 

Current  Machines  respectively,  and  for  Students  proficient  in  mathematics. 

DYNAMO,    MOTOR    AND    SWITCHBOARD    CIRCUITS 
FOR  ELECTRICAL  ENGINEERS. 

A  Practical  Book  dealing  with  the  subject  of  Direct,  Alternating  and 
Polyphase  Currents.     By  WILLIAM  R.  BOWKER,  C.E.,  M.E.,  E.E.,  Con- 
sulting Tramway  Engineer.     8vo,  cloth.  82.25 
"Mr.  Bowker's  book  consists  chiefly  of  diagrams  of  connections,  with  short 
explanatory  notes,  there  are  over  100  diagrams,  and  the  cases  considered 
cover  all  tne  more  important  circuits,  whether  in  direct  current,  single- 
phase,  or  polyphase  work." — Nature. 

ARMATURE      WINDINGS      OF      DIRECT      CURRENT 
DYNAMOS. 

Extension  and  Application  of  a  General  Winding  Rule.  By  E.  ARNOLD, 
Translated  from  the  German  by  F.  B.  DB  GREES.  8vo,  cloth.  82. OO 

POWER   TRANSMITTED    BY    ELECTRICITY, 

And  applied  by  the  Electric  Motor,  including  Electric  Railway  Con- 
struction. By  P.  ATKINSON,  A.M.,  Ph.D.  Third  Edition.  Fully  Re- 
vised, and  New  Matter  added.  With  94  Illustrations.  12mo,  cloth. 

82.00 
DYNAMO    CONSTRUCTION. 

A  Practical  Handbook  for  the  Use  of  Engineer-Constructors  and  Elec- 
tricians-in-Charge.  Embracing  Framework  Building.  Field  Magnet  and 
Armature  Winding  and  Grouping,  Compounding.  Ac.  By  J.  W.  URQU- 
HART.  Second  Edition,  Enlarged,  with  114  Illustrations.  12mo,  cloth. 

83.00 
HOW   TO    MAKE    A    DYNAMO. 

A  Practical  Treatise  for  Amateurs.  Containing  Illustrations  and  De- 
tailed Instructions  for  Constructing  a  Small  Dynamo  to  Produce  the 
Electric  Light.  By  ALFRED  CROFTS.  Seventh  Edition.  12mo,  cloth. 

.80 
WIRELESS  TELEGRAPHY; 

Its  Origins,  Development,  Inventions,  and  Apparatus.  By  CHARLES 
HENRY  SKWALL.  With  85  Diagrams  and  Illustrations.  8vo,  cloth. 

Net  82.00 


30        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
SUBMARINE   TELEGRAPHS; 

Their  History,  Construction,  and  Working.  Founded  in  part  on  WUN- 
SCHENDORFFTS  "Traite"  de  Te'le'graphie  Sous-Marine,"  and  Compiled  from 
Authoritative  and  Exclusive  Sources.  By  CHARLES  BRIGHT,  F.R.S.E. 
A.M.Inst.C.E.,  M.I.E.E.  780  pp.,  fully  Illustrated,  including  Maps  and 
Folding  Plates.  Royal  8vo,  cloth $£5.00 

ELECTRICAL   AND    MAGNETIC   CALCULATIONS. 

For  the  Use  of  Electrical  Engineers  and  Artisans,  Teachers,  Students, 
and  all  others  interested  in  the  Theory  and  Application  of  Electricity 
and  Magnetism.  By  Prof.  A.  A.  ATKINSON,  Ohio  University.  12mo, 

clo*h • $1.50 

"To  teachers  and  those  who  already  possess  a  fair  knowledge  of  their  sub- 
ject we  can  recommend  this  book  as  being  useful  to  consult  when  requiring 
data  or  formulae  which  it  is  neither  convenient  nor  necessary  to  retain  by 
memory." — The  Electrician. 

THE    ELECTRICAL    ENGINEER'S    POCKET-BOOK. 

Consisting  of  Rules,  Formulae,  Tables,  and  Data.  By  H.  R.  KEMFE, 
M.I.E.E.,  A.M.Inst.C.E.,  Technical  Officer  Postal  Telegraphs,  Author 
of  "A  Handbook  of  Electrical  Testing."  Second  Edition.  32mo, 
leather $1.75 


ELECTRIC  LIGHTING  (ELEMENTARY  PRINCIPLES  OF). 

By  ALAN  A.  CAMPBELL  SWINTON,  M.Inst.C.E.,  M.I.E.E.  Sixth  Edition. 
With  16  Illustrations.     12mo,  cloth .go 


ELECTRIC    LIGHT. 

Its  Production  and  Use,  Embodying  Plain  Directions  for  the  Treatment 
of  Dynamo-Electric  Machines,  Batteries,  Accumulators,  and  Electric 
Lamps.  By  J.  W.  URQUHART,  C.E.  Seventh  Edition.  12mo,  cloth. 

$3.00 

ELECTRIC    LIGHT    FOR   COUNTRY    HOUSES. 

A  Practical  Handbook  on  the  Erection  and  Running  of  Small  Installa- 
tions, with  Particulars  of  the  Cost  of  Plant  and  Working.  By  J.  H. 
KNIGHT.  Fourth  Edition,  Revised.  12mo,  boards  ..........  .50 

ELECTRIC    LIGHT    FITTING. 

A  Handbook  for  Working  Electrical  Engineers,  embodying  Practical 
Notes  on  Installation  Management.  By  J.  W.  URQUHART.  With 
numerous  Illustrations.  Fourth  Edition,  Revised.  12mo,  cloth.  $2.00 

ELECTRIC    SHIP=LIGHTING. 

A  Handbook  on  the  Practical  Fitting  and  Running  of  Ships'  Electrical 
Plant.  For  the  Use  of  Shipowners  and  Builders,  Marine  Electricians, 
and  Seagoing  Engineers-in-Charge.  By  J.  W.  URQUHART,  C.E.  Third 
Edition,  Revised  and  Extended.  With  88  Illustrations,  12mo, 
cloth  ...................................................  $3.00 

DYNAMIC    ELECTRICITY    AND    MAGNETISM. 

By  PHILIP  ATKINSON,  A.M.,  Ph.D.,  Author  of  "Elements  of  Static 
Electricity,"  &c.  Crown,  8vo,  417  pp.,  with  120  Illustrations,  cloth 


THE    STUDENT'S   TEXT=BOOK   OF    ELECTRICITY. 

By   H.   M.   NOAD,   F.R.S.     650   pp.,   with   470   Illustrations.     12mo, 
cloth  ...................................................  $4.00 


ARCHITECTURE,  BUILDING,  &c.  31 

ARCHITECTURE,   BUILDING,   ETC. 


SPECIFICATIONS    IN    DETAIL. 

By  FRANK  W.  MACEY,  Architect.  Author  of  "Conditions  of  Contract." 
Second  Edition,  Revi?<ed  and  Enlarged,  containing  644  pp.,  and  U,()00 
Illustrations.  Royal  8vo,  cloth..  8S.OO 

SITMMARY  OP  CONTENTS: — GKNEKAL  NOTES  (INCLUDING  POINTS  IN  SPECI- 
FICATION WRITING,  THE  ORDER  OK  A  SPECIFICATION.  AND  NOTKS  ON  ITKMH 
OFTEN  OMITTED  FROM  A  SPECIFICATION). — FORM  OF  OUTSIDE  COVER  TO  A 
SPECIFICATION. — SPECIFICATION  OF  WORKS  AND  LIST  OF  GENERAL  CONDI- 
TIONS.— PRELIMINARY  ITEMS  (INCH-DIN*?  SHOHIM;  AND  HOI-HE  BRKAKEH). 

—  DRAINAGE  (INCLUDING  RAIN-WATER  WELLS  AND  REPORTS).  — EXCAVATOR 
(INCLUDING  CONCRETE  FLOORS,  HOOFS,  STAIRS,  AND  WALLS).  -PAVIOR. — 
BRICKLAYER  (INCLUDING  FLINTWOHK.  RIVER,  AND  OTHER  WALLING,  SPRING- 
WATER  WELLS,  STORAGE  TANKS,  FOUNTAINS,  FILTERS,  TERRA  COTTA  AND 
FAIENCE). — MASON. — CARPENTER.  JOINER.  AND   IRONMONGER  (INCLUDING 
FENCING  AND  PILING). — SMITH  AND  FOUNDER  (INCLUDING  HEATING.  FIRE 
HYDRANTS,  STABLE  AND  COW-HOUSE  FITTINGS). — SLATER  (INCLUDING  SLATB 
MASON). — TILER. — STONE  TILER. — SHINGLER. — THATCHER. — PLUMBER  (IN- 
CLUDING HOT- WATER  WORK). — ZINCWORKEH. — COPPERSMITH.— PLASTERER. 

—  GASFTTTER.  —  BELLHANOER.  —  GLAZIER.  —  PAINTER. —  PAPEHH  ANGER. — 
GENERAL    REPAIRS  AND   ALTERATIONS. — VENTILATION. — ROAD-MAKING. — 
ELECTRIC  LIGHT. — INDEX. 

PRACTICAL    BUILDING  CONSTRUCTION. 

A  Handbook  for  Students  Preparing  for  Examinations,  and  a  Book 
of  Reference  for  Persons  F'ngaged  in  Building.  By  JOHN  PARNELL 
ALLEN,  Surveyor,  Lecturer  on  Building  Construction  at  the  Durham 
College  of  Science,  Newcastle-on-Tyne.  Fourth  Edition,  Revised  and 
Enlarged.  Medium  8vo,  570  pp.,  with  over  1,000  Illustrations,  cloth, 

83.00 
SPECIFICATIONS    FOR    PRACTICAL    ARCHITECTURE. 

A  Guide  to  the  Architect.  Engineer.  Surveyor,  and  Builder.  Upon 
the  Basis  of  the  Work  by  A.  BARTHOLOMEW.  Revised,  by  F.  ROGERS. 
8vo,  cloth.  ..  86.0O 

SCIENCE   OF   BUILDING: 

An  Elementary  Treatise  on  the  Principles  of  Construction.  By  E. 
WYNDHAM  TARN,  M.A.Lond.  Fourth  Edition.  12mo,  cloth. gl. 49 

ART   OF   BUILDING, 

Rudimentsof.  General  Principles  of  Construction,  Character.  Strength, 
and  Use  of  Materials,  Preparation  of  Specifications  and  Estimates,  Ac. 
By  EDWARD  DOBSON,  M.Inst.C.E.  Fifteenth  Edition,  revised  by  J.  P. 
ALLEN,  Lecturer  on  Building  Construction  at  the  Durham  College  of 
Science.  12mo,  cloth ...  .80 

BOOK   ON   BUILDING, 

Civil  and  Ecclesiastical.  By  Sir  EDMUND  BECKETT,  Bart.,  LL.D. 
Second  Edition.  12mo,  cloth..  .  .  81.80 

BUILDING    ESTATES: 

A  Treatise  on  the  Development,  Sale,  Purchase,  and  Management  of 
Building  Land.  By  F.  MAITLAND.  Fourth  Edition.  12mo,  cloth, 

.80 

COTTAGE   BUILDING. 

By  C.  BRUCE  ALLEN.  Twelfth  Edition,  with  Chapter  on  Economic 
Cottages  for  Allotments  by  Er  E.  ALLEN,  C.E.  12mo,  cloth  .  ,£Q 


32        CROSBY  LOCKWOOD  6r-  SON'S  CATALOGUE. 
DWELLING=HOUSES, 

Erection  of,  illustrated  by  a  Perspective  View,  Plans,  Elevations,  and 
Sections  of  a  Pair  of  Villas,  with  the  Specification,  Quantities,  and 
Estimates.  By  S.  H.  BROOKS.  12mo,  cloth $1.00 

FARM    BUILDINGS: 

Their  Arrangement  and  Construction,  with  Plans  and  Estimates.  By 
Professor  J.  SCOTT.  12mo,  cloth ^gQ 

SHORING, 

And  its  Application.    By  G.  H.  BLAGROVE.    Crown  8vo,  cloth.       .gQ 

ARCHES,    PIERS,    BUTTRESSES. 

By  WILLIAM  BLAND.      12mo,  cloth ^gQ 

PRACTICAL   BRICKLAYING. 

General  Principles  of  Bricklaying;  Arch  Drawing,  Cutting,  and  Setting; 
Pointing;  Paving,  Tiling,  &c.  By  ADAM  HAMMOND.  With  68  Wood- 
cuts. 12mo,  cloth ^gQ 

ART  OF  PRACTICAL  BRICK=CUTTING  AND  SETTING. 

By  ADAM  HAMMOND.     With  90  Engravings.     12mo,  cloth.  .  .  .       .g() 

BRICKWORK: 

Embodying  the  General  and  Higher  Principles  of  Bricklaying,  Cutting, 
and  Setting;  with  the  Application  of  Geometry  to  Roof  Tiling,  &c. 

By  F.  WALKER.     12mo,  cloth ^gQ 

"Contains  all  that  a  student  needs  to  learn  from  books. — Building  News." 

BRICKS   AND    TILES, 

Rudimentary  Treatise  on  the  Manufacture  of.  Containing  an  Outline 
of  the  Principles  of  Brickmaking.  By  E.  DOBSON,  M.R.I.B.A.  Addi 
tions  by  C.  TOMLINSON,  F.R.S.  Illustrated.  12mo,  cloth.  .  .  .$1.20 

PRACTICAL   BRICK   AND   TILE    BOOK. 

Comprising:  Brick  and  Tile  Making,  by  E.  DOBSON,  M.Inst.C.E. ;  Prac- 
tical Bricklaying  by  A.  HAMMOND,  Brick-Cutting  and  Setting,  by  A. 
HAMMOND.  550  pp.,  with  270  Illustrations,  strongly  half-bound .  $2.40 

PRACTICAL   MASONRY. 

A  Guide  to  the  Art  of  Stone  Cutting.  Comprising  the  Construction, 
Setting-Out,  and  Working  of  Stairs,  Circular  Work,  Arches,  Niches, 
Domes,  Pendentives,  Vaults,  Tracery  Windows,  &c.;  to  which  are 
added  Supplements  relating  to  Masonry  Estimating  and  Quantity  Sur- 
veying, and  to  Building  Stones  and  Marbles,  and  a  Glossary  of  Terms. 
For  the  Use  of  Students,  Masons,  and  Craftsmen.  By  W.  R.  PURCHASE, 
Building  Inspector  to  the  Borough  of  Hove.  Fifth  Edition,  Enlarged. 
Royal  8vo,  226  pp.,  with  52  Plates,  comprising  over  400  Diagrams, 
cloth $3.OO 

MASONRY    AND   STONECUTTING, 

The  Principles  of  Masonic  Projection,  and  their  Application  to  Con- 
struction. By  E.  DOBSON,  M.R.I.B.A.  12mo,  cloth $1.00 

MODERN    LIGHTNING    CONDUCTORS. 

An  Illustrated  Sunplement  to  the  Report  of  the  Lightning  Research 
Committee  of  1905,  with  Notes  as  to  the  Methods  of  Protection,  and 
Specifications.  By  KILLINGWORTH  HEDGES,  M.Inst.C.E.,  M.I.E.E., 
Honorary  Secretary  to  the  Lightning  Research  Committee,  Author  of 
"American  Street  Railways."  Medium  8vo,  cloth 

[Just  Published      Net  $3.OO 

"The  illustrations  are  very  interesting  and  give  one  a  clear  idea  of  what 
is  likely  to  happen  when  a  building  is  struck  by  lightning.  Mr.  Hedges' 
suggestions  of  possible  reasons  why  certain  protected  buildings  were  struck 


ARCHITECTURE,  BUILDING,  &c.  33 

are  instructive.  He  also  explains  the  modern  methods  of  fitting  buildings 
with  lightning  conductors.  To  the  ordinary  reader  the  book  will  be  of  in- 
terest, and  to  anyone  who  has  to  design  a  system  for  protecting  a  building 
from  lightning  strokes  it  will  be  helpful  " — Builder. 

PLUMBING: 

A  Text-Book  to  the  Practice  of  the  Art  or  Craft  of  the  Plumber.  With 
Chapters  upon  House  Drainage  and  Ventilation.  By  WM.  PATON 
BUCK  AN.  Ninth  Edition,  with  512  Illustrations.  Crown  8vo,  cloth. 

81.40 
HEATING    BY    HOT    WATER, 

VENTILATION    AND    HOT   WATER    SUPPLY. 

By  WALTER  JONES,  M.I.M.K.  360  pages,  with  140  Illustrations. 
Medium  8vo,  cloth.  .  •  • -83.5O 

THE    PRACTICAL    PLASTERER: 

A  Compendium  of  Plain  and  Ornamental  Planter  WTork.  By  W.  KKMP. 
12mo,  cloth.  .  .  .  .HO 

CONCRETE:    ITS    NATURE   AND    USES. 

A  Book  for  Architects.  Builders.  Contractor?,  and  Clerks  of  Work.*.  By 
G  L  SUTCLIFFE,  A.H.I.B.A.  Second  Edition,  Revised  and  Enlarged. 
396  pp.,  with  Illustrations.  12mo,  cloth  .  .  .[Juit  Published.  g:i.;>O 

PORTLAND   CEMENT    FOR    USERS. 

By  the  late  HENRY  FAIJA.  M.Inst.C.E.  Fifth  Edition.  Revised  and 
Enlarged  by.D.  B.  BUTLER,  AM  Inst.C.E.  12mo,  cloth 81. 2O 

LIMES,  CEMENTS,  MORTARS,  CONCRETES,  MASTICS, 
PLASTERING,   Ac. 

By  G.  R.  BURNELL,  C.E.     Fifteenth  Edition.     12mo,  cloth..  .         .60 

MEASURING    AND   VALUING    ARTIFICERS'    WORK 

(The  Student's  Guide  to  the  Practice  of).  Containing  Directions  for 
taking  Dimensions.  Abstracting  the  same,  and  bringing  the  Quantities 
into  Bill,  with  Tables  of  Constants  for  Valuation  of  Labour,  and  for  the 
Calculation  of  Areas  and  Solidities.  Originally  edited  by  E.  DOBHON. 
Architect.  With  Additions  by  E.  W.  TARN.  M.A.  Seventh  Edition. 
Revised.  12mo,  cloth.  . .  83.OO 

QUANTITIES    AND    MEASUREMENTS, 

In    Bricklayers'.    Masons'.    Plasterers',    Plumbers',    Painters'.    Paper 

hangers'.  Gilders',  Smiths'.  Carpenters'  and  Joiners'  Work.     By  A.  C 

BEATON,  Surveyor.     12mo.  cloth..  .  .60 

"This  book  is  indispensable  to  builders  and  their  quantity  clerks."— Enr 

li»h  Mechanic. 

TECHNICAL   GUIDE,    MEASURER,    AND    ESTIMATOR. 

For  Builders  and  Surveyors.  Containing  Technical  Directions  for  Meas- 
uring Work  in  all  the  Building  Trades.  'Complete  Specifications  for 
Houses,  Roads,  and  Drains,  and  an  Easy  Method  of  Estimating  the 
parts  of  a  Building  collectively.  By  A.  C.  BEATON.  Tenth  Edition. 

Waistcoat -pocket  size .60 

"No   builder,   architect,   surveyor,   or  valuer    should    be    without    his 
'Beaton.'" — Building  Newt. 

COMPLETE    MEASURER; 

Setting  forth  the  Measurement  of  Boards.  Glass,  Timber,  and  Stone. 
By  R.  HORTON.  Sixth  Edition.  12mo,  cloth Si. (JO 

ARCHITECTURAL    PERSPECTIVE. 

The  whole  Course  and  Operations  of  the  Draughtsman  in  Drawing  a 
Large  House  in  Linear  Perspective.  Illustrated  by  43  Folding  Plates. 
By  F.  O.  FERGUSON.  Third  Edition.  8vo,  boards 81. 5O 


34        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
PERSPECTIVE    FOR   BEGINNERS 

For  Students  and  Amateurs  in  Architecture,  Painting,  &c.  By  G. 
PYNE.  Crown  8vo,  cloth ,8Q 

PRACTICAL    RULES   ON    DRAWING. 

For  the  Builder  and  Young  Student  in  Architecture.     By  G.  PYNE.     4to 

$3.00 

THE    MECHANICS   OF   ARCHITECTURE. 

A  Treatise  on  Applied  Mechanics,  especially  Adapted  to  the  Use  of 
Architects.  By  E.  W.  TARN,  M.A.,  Author  of  "The  Science  of  Build- 
ing," &c.  Second  Edition,  Enlarged.  Illustrated  with  125  Diagrams. 
12mo,  cloth.  .  .  .  &3.00 

' '  The  book  is  a  very  useful  and  helpful  manual  of  architectural  mechan- 
ics."— Builder. 

A    HANDY    BOOK   OF   VILLA    ARCHITECTURE. 

Being  a  Series  of  Designs  for  Villa  Residences  in  various  Styles.  With 
Outline  Specifications  and  Estimates.  By  C.  WICKES,  Architect,  Au- 
thor of  "The  Spires  and  Towers  of  England,"  &c.  61  Plates,  4to,  half- 
morocco,  gilt  edges $12.00 

DECORATIVE    PART   OF   CIVIL   ARCHITECTURE. 

By  Sir  WILLIAM  CHAMBERS,  F.R.S.  With  Portrait,  Illustrations,  Notes, 
and  an  EXAMINATION  OF  GRECIAN  ARCHITECTURE,  by  JOSEPH  GWILT, 
F.S.A.  Revised  and  Edited  by  W.  H.  LEEDS.  66  Plates,  4to,  cloth. 

$8.40 

HINTS   TO   YOUNG    ARCHITECTS. 

By  GEORGE  WIGHTWICK,  Architect,  Author  of  "The  Palace  of  Archi- 
tecture," &c.,  &c.  Sixth  Edition,  revised  and  enlarged  by  G.  HUSKIS- 
SON  GUILLAUME,  Architect.  12mo,  cloth $1.40 

THE   ARCHITECTS'    GUIDE. 

Being  a  Text-book  of  Useful  Information  for  Architects,  Engineers,  Sur- 
veyors, Contractors,  Clerks  of  Works,  &c.  By  F.  ROGERS.  12mo, 

$1.40 
ARCHITECTURE— ORDERS. 

The  Orders  and  their  ^Esthetic  Principles.     By  W.  H.  LEEDS.     12mo. 

.60 
ARCHITECTURE— STYLES. 

The  History  and  Description  of  the  Styles  of  Architecture  of  Various 
Countries,  from  the  Earliest  to  the  Present  Period.  By  T.  TALBOT 
BURY,  F.R.I.B.A.,  &c.  Illustrated.  12mo,  cloth .80 

"ORDERS  AND  STYLES  OF  ARCHITECTURF,"  in  One  Vol $1.40 

ARCHITECTURE—DESIGN. 

The  Principles  of  Design  in  Architecture,  as  deducible  from  Nature  and 
exemplified  in  the  Works  of  the  Greek  and  Gothic  Architects.  By  EDW. 
L.  GARBETT,  Architect.  12mo,  cloth $1.00 

"We  know  no  work  that  we  would  sooner  recommend  to  an  attentive 
reader  desirous  to  obtain  clear  views  of  the  nature  of  architectural  art.  The 
book  is  a  valuable  one." — Builder. 

***  The  three  preceding  Works  in  One  handsome  Vol..  half -bound,  entitled 
"MODERN  ARCHITECTURE,"  price, $2.40 

ARCHITECTURAL   MODELLING    IN    PAPER, 

The  Art  of.     By  T.  A.  RICHARDSON.     12mo,  cloth. .60 


SANITATION  AND   WATER  SUPPLY.  35 

VITRUVIUS-THE      ARCHITECTURE      OF      MARCUS 

VITRUVIUS   POLLIO. 

In   Ten   Books.     Translated  from  the  Latin  by  J.  GWILT.     With  23 

Plates.      12mo.  cloth.  .  .  .gg.QO 

N.B. — This  is  the'jonly  Edition  of  VITRUVIUS  procurable  at  a  moderate  price. 

GRECIAN    ARCHITECTURE, 

An  Inquiry  into  the  Principles  of  Beauty  in;    with  an  Historical  View 

of  the  Ki.se  and  Progress  of  the  Art  in  Greece.     By  the  KARL  OK  AHKK 

DKKN.  .  .40 

%*  The  two  preceding  Works  in  One  htind»ome.  Volume,  halj-bountl.  entitled 

"ANCIENT  ARCHITECTURC,"  in- ice 82. 4O 

ACOUSTICS   OF    PUBLIC   BUILDINGS: 

The  Laws  of  Sound  as  applied  to  the  Arrangement  of  Buildings.  By 
Professor  T.  ROGERS  SMITH.  F.K.I.B.A.  New  Edition,  revised.  With 
numerous  Illustrations.  12mo,  cloth..  .  .»;<) 

LIGHT: 

An  Introduction  to  the  Science  of  Optics.  Designed  for  the  I'se  of 
Students  of  Architecture.  Engineering,  and  other  Applied  Sciences.  By 
E.  W.  TARN,  M.A.  12mo.  cloth ...  .(JO 


SANITATION   AND   WATER   SUPPLY. 


THE   HEALTH    OFFICER'S    POCKET-BOOK. 

A  Guide  to  Sanitary  Practice  and  Law.  For  Medical  Officers  of  Health, 
Sanitary  Inspectors,  Mem  here  of  Sanitary  Authorities,  Ac.  By  EDWARD 
F.  WILLOUGHBY.  M.D.  (Lond.),  Ac.  Second  Edition,  Kevised  and  En- 
larged. Fcap.  8vo,  leather. ...  S  I  .OO 

THE    WATER    SUPPLY    OF   TOWNS   AND    THE    CON- 
STRUCTION OF   WATER-WORKS. 

By  PROFESSOR  W.  K.  BURTON,  A.M.Inst.C.E.  Second  Edition,  Re- 
vised and  Extended.  Royal  8vo,  cloth.  (See  page  12.).  .  s:  ».nn 

THE   WATER    SUPPLY    OF   CITIES   AND   TOWNS. 

By  WILLIAM  HUMBER,  A.M.Inst.C.E.,  and  M.Inst.M.E.  Imp.  4to,  half- 
bound  morocco.  (See  page  12.).  .  845.OO 

WATER    AND    ITS    PURIFICATION. 

A  Handbook  for  the  Use  of  Local  Authorities,  Sanitary  Officers,  and 
others  interested  in  Water  Supply.  By  S.  RIDEAL,  D.Sc.  Lond.,  F.I.C. 
Second  Edition,  Revised,  with  Additions,  including  numerous  Illustra- 
tions and  Tables.  12mo,  cloth.  .  s:  ;.<»<> 

RURAL   WATER    SUPPLY. 

A  Practical  Handbook  on  the  Supply  of  Water  and  Construction  of 
Water-works  for  Small  Country  Districts.  By  ALLAN  GREENWELL, 
A.M.I.C.E.,  and.W.  T.  CURRY.  A.M.I.C.E.  Revised  Edition.  12mo, 
doth..  82.00 

WATER    ENGINEERING. 

A  Practical  Treatise  on  the  Measurement,  Storage,  Conveyance,  ana 
Utilisation  of  Water  for  the  Supply  of  Towns.  By  C.  SLAGO,  A.M. 
Inst.C.E .$3.00 


36        CROSBY  LOCKWOOD  &•  SON'S  CATALOGUE. 
THE    PURIFICATION   OF   SEWAGE. 

Being  a  Brief  Account  of  the  Scientific  Principles  of  Sewage  Purifica- 
tion, and  their  Practical  Application.  By  SIDNEY  BARWISE,  M.D 
(Lond.),  B.Sc.,  M.R.C.S.,  D.P.H.  (Camb.),  Fellow  of  the  Sanitary  In- 
stitute, Medical  Officer  of  Health  to  the  Derbyshire  County  Council. 
Second  Edition,  Revised  and  Enlarged,  with  an  Appendix  on  the  Analy- 
sis of  Sewage  and  Sewage  Effluents.  With  numerous  Illustrations  and 

Diagrams.     Demy  8vo,  cloth Net  $3.50 

SUMMARY  OF  CONTENTS: — SEWAGE:  ITS  NATURE  AND  COMPOSITION. — 
THE  CHEMISTRY  OF  SEWAGE. — VARIETIES  OF  SEWAGE  AND  THE  CHANGES  IT 
UNDERGOES. — RIVER  POLLUTION  AND  ITS  EFFECTS. — THE  LAND  TREATMENT 
OF  SEWAGE. — PRECIPITATION,  PRECIPITANTS,  AND  TANKS. — THE  LIQUEFAC- 
TION OF  SEWAGE. — PRINCIPLES  INVOLVED  IN  THE  OXIDATION  OF  SEWAGE. — 
ARTIFICIAL  PROCESSES  OF  PURIFICATION. — AUTOMATIC  DISTRIBUTORS  AND 
SPECIAL  FILTERS. — PARTICULARS  OF  SEWERAGE  AND  SEWAGE  DISPOSAL 
SCHEMES  REQUIRED  BY  LOCAL  GOVERNMENT  BOARD. — USEFUL  DATA. — Ap- 
pendix: THE  APPARATUS  REQUIRED  FOR  SEWAGE  ANALYSIS. — STANDARD 
SOLUTIONS  USED  IN  THE  METHOD  OF  SEWAGE  ANALYSIS. — Tables:  ESTI- 
MATION OF  AMMONIA. — NITROGEN  AS  NITRATES. — INCUBATOR  TEST,  OXYGEN 
ABSORBED. — To  CONVERT  GRAINS  PER  GALLON  TO  PARTS  PER  100,000. 

SANITARY  WORK  IN  SMALL  TOWNS  AND  VILLAGES. 

By  CHARLES  SLAGG,  A.M.Inst.C.E.  Third  Edition,  Enlarged.  12mo 
doth $3.00 

VENTILATION: 

A  Text-Book  to  the  Practice  of  the  Art  of  Ventilating  Buildings.  By 
W.  P.  BUCHAN.  With  170  Illustrations.  12mo,  cloth $1.40 


CARPENTRY,   TIMBER,   ETC. 


PRACTICAL    FORESTRY. 

And  its  Bearing  on  the  Improvement  of  Estates.  By  CHARLES  E. 
CURTIS,  F.S.I.,  Professor  of  Forestry,  Field  Engineering,  and  General 
Estate  Management,  at  the  College  of  Agriculture,  Downton.  Second 

Edition,  Revised.     12mo,  cloth $1.40 

PREFATORY  REMARKS. — OBJECTS  OF  PLANTING. — CHOICE  OF  A  FORESTER. 
— CHOICE  OF  SOIL  AND  SITE. — LAYING  OUT  OF  LAND  FOR  PLANTATIONS.— 
PREPARATION  OF  THE  GROUND  FOR  PLANTING. — DRAINAGE. — PLANTING. — 
DISTANCES  AND  DISTRIBUTION  OF  TREES  IN  PLANTATIONS. — TREES  AND 
GROUND  GAME. — ATTENTION  AFTER  PLANTING. — THINNING  OF  PLANTATIONS. 
— PRUNING  OF  FOREST  TREES. — REALIZATION. — METHODS  OF  SALE. — 
MEASUREMENT  OF  TIMBER. — MEASUREMENT  AND  VALUATION  OF  LARCH'S 
PLANTATION. — FIRE  LINES. — COST  OF  PLANTING. 

WOODWORKING    MACHINERY. 

Its  Rise,  Progress,  and  Construction.  With  Hints  on  the  Management 
of  Saw  Mills  and  the  Economical  Conversion  of  Timber.  Illustrated 
with  Examples  of  Recent  Designs  by  leading  English,  French,  and 
American  Engineers.  By  M.  Powis  BALE,  M.Inst.C.E.,  M.I.Mech.E. 
Second  Edition,  Revised,  with  large  Additions.  8vo,  440  pp.,  cloth, 

$3.50 

SAW   MILLS. 

Their  Arrangement  and  Management,  and  the  Economical  Conversion 
of  Timber.  By  M.  Powis  BALE,  M.Inst.C.E.,  M.I.Mech.E.  Second 
Edition,  Revised.  12mo,  cloth $4.00 


CARPENTRY,  TIMBER,  &c.  37 

THE   ELEMENTARY    PRINCIPLES   OF   CARPENTRY. 

A  Treatise  on  the  Pressure  and  Equilibrium  of  Timber  Framing,  the 
Resistance  of  Timber,  and  the  Construction  of  l-'loors.  Arches,  Bridges, 
Roofs,  Uniting  Iron  and  Stone  with  Timber,  «tc.  To  which  is  added 
an  Essay  on  the  Nature  and  Properties  of  Timber,  &c.,  with  Ascrip- 
tions of  the  kinds  of  Wood  used  in  Building;  also  numerous  Tables 
of  the  Scantlings  of  Timber  for  different  purposes,  the  Si>ecilic  Gravi- 
ties of  Materials,  <kc.  By  THOMAS  TREIHJOLD.  C.E.  With  an  Ap|>endix 
of  Specimens  of  Various  Roofs  of  Iron  and  Stone,  Illustrated.  Seventh 
Edition,  thoroughly  Revised  and  considerably  Enlarged  by  E.  WYND- 
HAM  TAKN,  M.A..  Author  of  "The  Science  of  Building."  Ac.  With 
61  Plates,  Portrait  of  the  Author,  and  several  Woodcuts.  In  One 
large  Vol.,  4to,  cloth 310.OO 

THE   CARPENTER'S  GUIDE. 

Or,  Book  of  Lines  for  Carpenters;  comprising  all  the  Elementary  Prin- 
ciples essential  for  acquiring  a  knowledge  of  C'arnentrv.  Founded  on 
the  late  PKTER  NICHOLSON'S  standard  work.  A  New  Edition,  Revised 
by  ARTHUR  AHHPITEL,  F.S.A.  Together  with  Practical  Rules  on 
Drawing,  by  GEORGE  PYNE.  With  74  Plates,  4to,  cloth 87.50 

CARPENTRY    AND   JOINERY- 

The  Elementary  Principles  of  Carpentry.  Chiefly  composed  from  the 
Standard  Work  of  T.  THKDGOLD.  With  Additions  and  a  Treatise  on 
Joinery  by  E.  W.  TARN,  M.A.  Eighth  Edition.  12mo,  clnth.§1.4<) 

Atlas  of  35  Plates  to  accompany  and  illustrate  the  foregoing  book. 

With  Descriptive  Letterpress.     4to. .  .  -82. 4O 

ROOF   CARPENTRY: 

Practical  Lessons  in  the  Framing  of  Wrood  Roofs.  For  the  use  of 
Working  Carpenters.  By  GEO.  COLLIXGS.  12mo,  cloth ..  .,SO 

CIRCULAR   WORK    IN   CARPENTRY   AND   JOINERY. 

A  practical  Treatise  on  Circular  Work  of  Single  and  Double  Curvature. 
By  GEOROR  Co  LUNGS.  Fourth  Edition.  12mo,  cloth 81.OO 

HANDRAILING   COMPLETE    IN    EIGHT   LESSONS. 

On  the  Square-Cut  System.  By  J.  S.  Goldthorp.  Teacher  of  Geometry 
and  Building  Construction  at  the  Halifax  Mechanics'  Institute.  With 
Eight  Plates  and  over  150  Practical  Exercises.  4to,  cloth  .  . .  .$1 .40 

PRACTICAL   TREATISE   ON    HANDRAILING: 

Showing  New  and  Simple  Methods.  By  GEO.  COLLINGH.  Third  Edi- 
tion, including  a  Treatise  on  Stairbuildmg.  12mo,  cloth 81. (K) 

THE    CABINET-MAKER'S    GUIDE    TO    THE    ENTIRE 

CONSTRUCTION   OF   CABINET   WORK. 

By  RICHARD  BITMF.AD.  Illustrated  with  Plans,  Sections  and  Working 
Drawings.  12mo,  cloth Sl.no 

THE   JOINTS   MADE    AND    USED   BY   BUILDERS. 

By  W.  J.  CHRISTY.     With  160  Woodcuts.     12mo,  cloth 81.20 

TIMBER    IMPORTER'S,    TIMBER   MERCHANT'S,    AND 

BUILDER'S   STANDARD   GUIDE. 
By  R.  E.  GRANDY.     12mo,  cloth .80 

TIMBER  MERCHANT'S  and  BUILDER'S  COMPANION. 

Containing  New  and  Copious  Tables  of  the  Reduced  Weight  and 
Measurement  of  Deals  and  Battens  of  all  sizes  and  other  Useful  Tables 
for  the  use  of  Timber  Merchants  and  Builders.  By  WILLIAM  DOWSING. 
Fifth  Edition,  Revised  and  Corrected.  12mo,  cloth $1.20 


38        CROSBY  LOCKWOOD  6-  SON'S 'CATALOGUE. 
THE    PRACTICAL   TIMBER   MERCHANT. 

Being  a  Guide  for  the  Use  of  Building  Contractors,  Surveyors,  Builders, 
&c.,  comprising  useful  Tables  for  all  purposes  connected  with  the 
Timber  Trade,  Marks  of  Wood,  Essay  on  the  Strength  of  Timber, 
Remarks  on  the  Growth  of  Timber,  &c.  By  W.  RICHARDSON.  Second 
Edition.  Fcap.  8vo,  cloth $1.40 

PACKING-CASE   TABLES. 

Showing  the  number  of  Superficial  Feet  in  Boxes  or  Packing-Cases, 
from  six  inches  square  and  upwards.  By  W.  RICHARDSON,  Timber 
Broker.  Fourth  Edition.  Oblong  4to,  cloth $1.40 

GUIDE   TO   SUPERFICIAL   MEASUREMENT. 

Tables  calculated  from  1  to  200  inches  in  length,  by  1  to  108  inches  in 
breadth.  For  the  use  of  Architects,  Surveyors,  Engineers,  Timber 
Merchants,  Builders,  &c.  By  J.  HAWKINGS.  Fifth  Edition.  12mo, 
cloth $1.40 


DECORATIVE  ARTS,  ETC. 


SCHOOL    OF    PAINTING     FOR    THE    IMITATION    OF 

WOODS  AND   MARBLES. 

As  Taught  and  Practised  by  A.  R.  VAN  DER  BURG  and  P.  VAN  DER 
BURG,  Directors  of  the  Rotterdam  Painting  Institutions.  Royal  folio, 
18^  by  12£  in.,  Illustrated  with  24  full-size  Coloured  Plates;  also  12 
plain  Plates,  comprising  154  Figures.  Fourth  Edition,  cloth. 

Net  $10.00 
LIST  OF  PLATES. 

1.  VARIOUS  TOOLS  REQUIRED  FOR  WOOD  PAINTING. — 2,3.  WALNUT:  PRE- 
LIMINARY STAGES  OF  GRAINING  AND  FINISHED  SPECIMEN. — 4.  TOOLS  USED 
FOR  MARBLE  PAINTING  AND  METHOD  OF  MANIPULATION. — 5,  6.  ST.  REMI 
MARBLE;  EARLIER  OPERATIONS  AND  FINISHED  SPECIMEN. — 7.  METHODS  OF 
SKETCHING  DIFFERENT  GRAINS,  KNOTS,  &c. — 8,  9.  ASH:  PRELIMINARY 
STAGES  AND  FINISHED  SPECIMEN. — 10.  METHODS  OF  SKETCHING  MARBLE 
GRAINS. — 11,12.  BRECHE  MARBLE;  PRELIMINARY  STAGES  OF  WORKING  AND 
FINISHED  SPECIMEN.^IS.  MAPLE  ;  METHODS  OF  PRODUCING  THE  DIFFERENT 
GRAINS. — 14,  15.  BIRD'S-EYE  MAPLE;  PRELIMINARY  STAGES  AND  FINISHED 
SPECIMEN. — 16.  METHODS  OF  SKETCHING  THE  DIFFERENT  SPECIES  OF  WHITE 
MARBLE. — 17,  18.  WHITE  MARBLE;  PRELIMINARY  STAGES  OF  PROCESS  AND 
FINISHED  SPECIMEN. — 19.  MAHOGANY;  SPECIMENS  OF  VARIOUS  GRAINS  AND 
METHODS  OF  MANIPULATION. — 20.  21,  MAHOGANY;  EARLIER  STAGES  AND 
FINISHED  SPECIMEN. — 22,  23,  24.  SIENNA  MARBLE;  VARIETIES  OF  GRAIN, 
PRELIMINARY  STAGES  AND  FINISHED  SPECIMEN. — 25,  26,  27.  JUNIPER  WOOD; 
METHODS  OF  PRODUCING  GRAIN,  &c. ;  PRELIMINARY  STAGES  AND  FINISHED 
SPECIMEN. — 28,  29,  30.  VERT  DE  MER  MARBLE;  VARIETIES  OF  GRAIN  AND 
METHODS  OF  WORKING,  UNFINISHED  AND  FINISHED  SPECIMENS. — 31,  32,  33. 
OAK;  VARIETIES  OF  GRAIN,  TOOLS  EMPLOYED  AND  METHODS  OF  MANIPU- 
LATION, PRELIMINARY  STAGES  AND  FINISHED  SPECIMEN. — 34,  35,  36.  WAUL- 
SORT  MARBLE;  VARIETIES  OF  GRAIN,  UNFINISHED  AND  FINISHED  SPECIMENS. 

ELEMENTARY    DECORATION: 

As  Applied  to  Dwelling-Houses,  &c.     By  J.  W.  FACET.     12mo,  cloth. 

80 

PRACTICAL   HOUSE    DECORATION. 

A  Guide  to  the  Art  of  Ornamental  Painting,  the  arrangement  of  Colours 
in  Apartments,  and  the  Principles  of  Decorative  Design.  By  JAMES  W. 

FACEY.     12mo,  cloth $1.00 

***  The  last  two  works  in  One  handsome  Vol.,  half -bound,  entitled  "  HOUSE 
DECORATION,  ELEMENTARY  AND  PRACTICAL,"  price $2.00 


DECORA TIVE  AR TS,  6rv.  39 

ORNAMENTAL  ALPHABETS,  ANCIENT  &  MEDIEVAL. 

From  the  Eighth  Century  with  Numerals;  including  (lot hie.  Church- 
Text,  large  and  small,  German,  Italian,  Arabesque,  Initials  for  Illum- 
ination, Monograms,  Crosses,  <fcc..  for  the  use  of  Architectural  and  En- 
gineering Draughtsmen.  Missal  Painters,  Masons.  Decorative  Painters, 
Lithographers,  Engravers,  Carvers,  Ac..  «tc.  Collected  and  Engraved 
by  K.  DKLAMOTTK,  and  printed  in  Colours.  New  and  Cheaper  Edition. 
Royal  8vo,  oblong,  ornamental  boards..  .  81. OO 

MODERN    ALPHABETS,    PLAIN    AND    ORNAMENTAL. 

Including  derm  an,  Old  English,  Saxon.  Italic,  Persi>ective,  Greek, 
Hebrew,  Court  Hand  Engrossing.  Tuscan.  Riband,  Gothic,  Hustic,  and 
Arabesque;  with  several  <  >riginal  Designs,  and  an  Analysis  of  the  Roman 
and  Old  English  Alphabets,  large  and  small,  and  Numerals,  for  the  use 
of  Draughtsmen,  Surveyors,  Masons.  Decorative  Painters.  Lithog- 
raphers, Engravers,  Carvers.  dec.  Collected  and  Engraved  bv  F.  DKLA- 
MOTTK,  and  printed  in  Colours.  New  and  Cheaj>er  Edition.  Royal  8\o, 
oblong,  ornamental  boards.  .  S  |  .nu 

MEDIEVAL   ALPHABETS   AND    INITIALS. 

By  F.  G.  DEI.AMOTTK.  Containing  21  Plates  and  Illuminated  Title 
printed  in  Gold  and  Colours.  With  an  Introduction  by  J.  WILLIS 
BROOKS.  Fifth  Edition.  Small  4to,  ornamental  boards.  ..  82. Oi) 

A    PRIMER   OF   THE   ART   OF    ILLUMINATION. 

For  the  Use  of  Beginners;  with  a  Rudimentary  Treatise  on  the  Art, 
Practical  Directions  for  its  Exercise,  and  Examples  taken  from  Illumi- 
nated MSS.,  printed  in  Gold  and  Colours.  By  F.  DELAMOTTE.  New 
and  Cheaper  Edition.  Small  4to,  ornamental  boards.  .  82. 4O 

THE    EMBROIDERER'S   BOOK   OF    DESIGN. 

Containing  Initials,  Emblems.  Cyphers,  Monograms.  Ornamental  Bor- 
ders, Ecclesiastical  Devices,  Mediirval  and  Modern  Alphabets,  and 
National  Emblems.  Collected  by  F.  DKLAMOTTK,  and  printed  in 
Colours.  Oblong  royal  8vo,  ornamental  wrapper.  .  S  1  .nu 

MARBLE    DECORATION 

And  the  Terminology  of  British  and  Foreign  Marbles.  A  Handbook 
for  Students.  By  GKOROK  H.  BLAOROVE,  Author  of  "Shoring  and  its 
Application,"  &c.  With  28  Illustrations.  12mo,  cloth 81.40 

THE   DECORATOR'S   ASSISTANT. 

A  Modern  Guide  for  Decorative  Artists  and  Amateurs.  Painters,  Writers, 
Gilders,  Ac.  Containing  upwards  of  GOO  Receipts,  Rules,  and  Instruc- 
tions; with  a  variety  of  Information  for  General  Work  connected  with 
every  Class  of  Interior  and  Exterior  Decorations,  Ac.  Eight  Edition 
1 2mo  .  .  .40 

GRAMMAR   OF   COLOURING. 

Applied  to  Decorative  Painting  and  the  Arts.  By  G.  FIELD.  New 
Edition,  enlarged  by  E.  A.  DAVIDSON.  With  Coloured  Plates.  12mo. 
cloth...  81.20 

HOUSE     PAINTING,     GRAINING,     MARBLING,      AND 

SIGN   WRITING. 

With  a  Course  of  Elementary  Drawing,  and  a  Collection  of  Useful 

Receipts.     By   E.   A.    DAVIDSON.     Ninth  Edition.     Coloured    Plates. 

12mo,  cloth.  .  82.OO 

ART   OF    LETTER    PAINTING    MADE    EASY. 

By  J.  G.  BA.DRN.OCH,  With  12  full-page  Engravings  of  Examples.    12mo, 

,00 


40        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
PAINTING    POPULARLY    EXPLAINED. 

By  THOMAS  JOHN  GULLICK,  Painter,  and  JOHN  TIMES,  F.S.A.  Includ- 
ing Fresco,  Oil,  Mosaic,  Water  Colour,  Water-Glass,  Tempera,  En- 
caustic, Miniature,  Painting  on  Ivory,  Vellum,  Pottery,  Enamel,  Glass, 

&c.     Sixth  Edition.     12mo,  cloth 852.00 

*#*  Adopted  as  a  Prize  Book  at  South  Kensington. 

GLASS   STAINING,    AND    PAINTING    ON    GLASS. 

From  the  German  of  Dr.  GESSERT  and  EMANUEL  OTTO  FROMBERG. 
With  an  Appendix  on  The  Art  of  Enamelling.  12mo,  cloth.  .$1.00 

WOOD=CARVING    FOR   AMATEURS. 

With  Hints  on  Design.  By  A  LADY.  With  10  Plates.  New  and 
Cheaper  Edition.  12mo,  in  emblematic  wrapper .£0 


NATURAL  SCIENCE,   ETC. 


THE   VISIBLE    UNIVERSE. 

Chapters  on  the  Origin  and  Construction  of  the  Heavens.  By  J.  E. 
GORE,  F.R.A.S.,  Author  of  "Star  Groups,"  &c.  Illustrated  by  6 
Stellar  Photographs  and  12  Plates.  Demy  8vo,  cloth, $3.75 

STAR    GROUPS. 

A  Student's  Guide  to  the  Constellations.  By  J.  ELLARD  GORE,  F.R.A.S. 
M.R.I. A.,  &c.,  Author  of  "The  Visible  Universe,"  "The  Scenery  of  the 
Heavens,"  &c.  With  30  Maps.  Small  4to,  cloth $2.00 

AN   ASTRONOMICAL   GLOSSARY. 

Or,  Dictionary  of  Terms  used  in  Astronomy.  With  Tables  of  Data  and 
Lists  of  Remarkable  and  Interesting  Celestial  Objects.  By  J.  ELLARD 
GORE,  F.R.A.S.  12mo,  cloth $1.00 

ASTRONOMY. 

By  the  late  Rev.  R.  MAIN,  M.A.,  F.R.S.  Third  Edition,  revised  by 
WILLIAM  THYNNE  LYNN,  B.A.,  F.R.A.S.  12mo,  cloth ,§O 

THE    MICROSCOPE. 

Its  Construction  and  Management.  Including  Technique,  Photo-micro- 
graphy, and  the  Past  and  Future  of  the  Microscope.  By  Dr.  HENRI 
VAN  HEURCK,  Re-Edited  and  Augumented  from  the  Fourth  French 
Edition,  and  Translated  by  WYNNE  E.  BAXTER,  F.G.S.  Imp.  8vo, 
doth $7.00 

MANUAL   OF  THE   MOLLUSCA: 

A  Treatise  on  Recent  and  Fossil  Shells.  By  Dr.  S.  P.  WOODWARD, 
A.L.S.  With  Appendix  by  RALPH  TATE,  A.L.S.,  F.G.S.  With 
numerous  Plates  and  300  Woodcuts.  12mo,  cloth, $3.00 

THE   TWIN    RECORDS   OF   CREATION. 

Or,  Geology  and  Genesis,  their  Perfect  Harmony  and  Wonderful  Con- 
cord. By  G.  W.  V.  LE  VAUX.  8vo,  cloth $2.00 

LARDNER'S   HANDBOOKS   OF   SCIENCE. 
HANDBOOK   OF   MECHANICS. 

Enlarged  and  re-written  by  B.  LOEWY,  F.R.A.S.    8vo,  cloth .  .$2.40 


CHEMICAL  MANUFACTURES,  CHEMISTRY,  d-r.  41 

LARDNER'S    HANDBOOKS   OF   SCIENCE  ~('ontinw<l. 

HANDBOOK     OF     HYDROSTATICS     AND     PNEU- 
MATICS. 
Re  vised  and  Enlarged  by  B.  LOEWT,  F.R.  A.S.    Post  8vo.  cloth,  g'>.(M) 

HANDBOOK   OF    HEAT. 

Edited  and  re-written  by  B.  LOKWY.  F.R.A.S.    Post  8v.,,  rl<>th,g'>.4() 

HANDBOOK   OF   OPTICS. 

New  Edition.     E<lited    by  T.  OLVF.R    HARDING.  B.A.     Small  8vo. 
doth •  •  -S3.OO 

ELECTRICITY,   MAGNETISM,   AND  ACOUSTICS. 

Edited  by  GEO.  C.  FOSTER.  B.A.     Small  8vo,  cloth 8*'.(M) 

HANDBOOK   OF    ASTRONOMY. 

Revised  and  Edited  by  EDWIN  DUNKIN.  F.R.A.S.    8vo,  cloth,  $;{.SO 

MUSEUM    OF   SCIENCE    AND   ART. 

With  upwards  of  1,200  Engravings.    In  Six  Double  Vola,  cloth,  j$7.;>O 
Half-morocco 81'-2.(>O 

NATURAL   PHILOSOPHY    FOR    SCHOOLS.       81. JO 

ANIMAL    PHYSIOLOGY    FOR   SCHOOLS 81.40 

THE    ELECTRIC   TELEGRAPH. 

Revised  by  E.  B.  BHKJHT,  K.R.A.S.     Fcap.  8vo,  cloth 81  .(M) 


CHEMICAL  MANUFACTURES, 
CHEMISTRY,   ETC. 


THE    OIL    FIELDS   OF    RUSSIA    AND   THE     RUSSIAN 
PETROLEUM   INDUSTRY. 

A  Practical  Handbook  on  the  Exploration,  Exploitation,  and  Manage- 
ment of  Russian  Oil  Properties,  including  Notes  on  the  Origin  of 
Petroleum  in  Russia,  a  Description  of  the  Theory  nnd  Practice  of 
Liquid  Fuel,  and  a  Translation  of  the  Rules  and  Regulations  concern- 
ing Russian  Oil  Properties.  By  A.  BKKBY  THOMPSON.  A.M.I.M.K., 
late  Chief  Engineer  and  Manager  of  the  Euroj>ean  Petroleum  Company's 
Russian  Oil  Properties.  About  500  pp..  with  numerous  Illustrations 
and  Photographic  Plates,  and  a  Map  ot  the  Balakhany-Saboontchy- 
Romany  Oil  Field.  Super-royal  8vo,  cloth Net  87.50 

THE  ANALYSIS  OF  OILS  AND  ALLIED  SUBSTANCES. 

By  A.  C.  WRIGHT,  M.A.Oxon.,  B.Sc.,  Lond.,  formerly  Assistant  Lecturer 
in  Chemistry  at  the  Yorkshire  College,  Leeds,  and  Lecturer  in  Chemis- 
try at  the  Hull  Technical  School.  Demy  8vo,  cloth &,'5.5O 

A    HANDYBOOK   FOR   BREWERS. 

Being  a  Practical  Guide  to  the  Art  of  Brewing  and  Malting.  Embracing 
the  Conclusions  of  Modern  Research  which  bear  upon  the  Practice  of 
Brewing.  By  HERBERT  EDWARDS  WRIGHT,  M.A.  Third  Edition, 
Enlarged.  530  pp.  12mo,  cloth In  preta 

A  POCKET-BOOK  OF  MENSURATION  AND  GAUGING. 

Containing  Tables,  Rules,  and  Memoranda  for  Revenue  Officers, 
Brewers,  Spirit  Merchants,  &c.  By  J.  B.  MANT,  Inland  Revenue. 
Second  Edition,  Revised.  18mo,  leather 81. GO 


42        CROSBY  LOCKWOOD  &-  SON'S  CATALOGUE. 
THE   GAS   ENGINEER'S   POCKET=BOOK. 

Comprising  Tables,  Notes  and  Memoranda  relating  to  the  Manufacture. 
Distribution  and  Use  of  Coal  Gas  and  the  Construction  of  Gas  Works. 
By  H.  O'CONNOR,  A.M.  Inst.C.E.  Second  Edition,  Revised.  470  pp., 
12mo.  fully  Illustrated,  leather $3.50 

LIGHTING   BY  ACETYLENE 

Generators,  Burners,  and  Electric  Furnaces.  By  WILLIAM  E.  GIBBS, 
M.E.  With  66  Illustrations.  12mo,  cloth $1.50 

ENGINEERING   CHEMISTRY. 

A  Practical  Treatise  for  the  Use  of  Analytical  Chemists,  Engineers, 
Iron  Masters,  Iron  Founders,  Students  and  others.  Comprising 
Methods  of  Analysis  and  Valuation  of  the  Principal  Materials  used  in 
Engineering  Work,  with  numerous  Analyses,  Examples  and  Suggestions. 
By  H.  JOSHUA  PHILLIPS,  F.I.C.,  F.C.S.  Third  Edition,  Revised  and 
Enlarged.  12mo,  420  pp.,  with|Plates  and  Illustrations,  cloth,  $4.50 

NITRO-EXPLOSIVES. 

A  Practical  Treatise  concerning  the  Properties,  Manufacture,  and 
Analysis  of  Nitrated  Substances,  including  the  Fulminates,  Smokeless 
Powders,  and  Celluloid.  By  P.  GERALD  SANFORD,  F.I.C.,  Consulting 
Chemist  to  the  Cotton  Powder  Company,  Limited,  &c.  With  Illustra- 
tions. 12mo,  cloth $3.00 

A   HANDBOOK   OF   MODERN    EXPLOSIVES. 

A  Practical  Treatise  on  the  Manufacture  and  Use  of  Dynamite,  Gun- 
Cotton,  Nitro-Glycerine  and  other  Explosive  Compounds,  including 
Collodion-Cotton.  With  Chapters  on  Explosives  in  Practical  Applica- 
tion. By  M.  EISSLER,  M.E.  Second  Edition,  Enlarged.  12mo,  cloth, 

$5.00 
DANGEROUS   GOODS. 

.Their  Sources  and  Properties,  Modes  of  Storage  and  Transport.  With 
Notes  and  Comments  on  Accidents  arising  therefrom.  A  Guide  for 
the  Use  of  Government  and  Railway  Officials,  Steamship  Owners,  &c. 
By  H.  JOSHUA  PHILLIPS,  F.I.C.,  F.C.S.  12mo,  374  pp.;  cloth,  $3.50 

"Merits  a  wide  circulation,  and  an  intelligent,  appreciative  study." — 
Chemical  News. 

A  MANUAL  OF  THE  ALKALI  TRADE. 

Including  the  Manufacture  of  Sulphuric  Acid,  Sulphate  of  Soda,  and 
Bleaching  Powder.  By  JOHN  LOMAS,  Alkali  Manufacturer.  With 
232  Illustrations  and  Working  Drawings.  Second  Edition,  with 
Additions.  Super-royal,  8vo,  cloth 810.00 

THE  BLOWPIPE  IN  CHEMISTRY,  MINERALOGY,  Etc. 

Containing  all  known  Methods  of  Anhydrous  Analysis,  many  Working 
Examples,  and  Instructions  for  Making  Apparatus.  By  Lieut. -Colonel 
W.  A.  Ross,  R.A.,  F.G.S.  Second  Ed.,  Enlarged.  Ll2mo,  cloth,  $2.00 

THE   MANUAL   OF   COLOURS   AND    DYE-WARES. 

Their  Properties,  Applications,  Valuations,  Impurities  and  Sophistica- 
tions. For  the  Use  of  Dyers,  Printers,  Drysalters,  Brokers,  &c.  By 
J.  W.  SLATER.  Second  Edition,  Revised  and  greatly  Enlarged.  12mo, 

cloth $3.00 

"  There  is  no  other  work  which  covers  precisely  the  same  ground.  To 

students  preparing  for  examinations  in  dyeing  and  printing  it  will  prove 

exceedingly  useful." — Chemical  News. 


INDUSTRIAL  AND  USEFUL  ARTS.  43 

THE   ARTISTS'    MANUAL   OF    PIGMENTS. 

Showing  their  Comjx»sition,  Conditions  of  Permanency,  Non-Per- 
manency, and  Adulterations,  <ic.,  with  Tests  of  Purity.  By  H.  C. 

STANDAGE.  Third  Edition.  12rno,  cloth.  .  81.OO 

"  This  work  is  indeed  multurn-in-parro,  and  we  can,  with  K'KK|  conscience, 

recommend  it  t(  all  who  come  in  contact  with  pigments,  whether  as  makers, 

dealers,  or  users.   — Chemical  Review. 


INDUSTRIAL  ARTS,   TRADES,   AND 
MANUFACTURES. 


THE    CULTIVATION    AND    PREPARATION    OF    PARA 

RUBBER. 

By  W.  H.  JOHNSON,  F.L.S.,  F.K.H.S.,  Director  of  Agriculture.  Gold 
Coast  Colony,  West  Africa,  Commissioned  by  Government  in  1902  to 
visit  Ceylon  to  Study  the  Methods  employed  there  in  the  Cultivation 
and  Preparation  of  Para  Rubljer  and  other  Agricultural  Staples  for 
Market,  with  a  view  to  Introduce  them  into  West  Africa.  Demy  RVO. 

doth 83.00 

SUMMARY  OF  CONTENTS: — INTRODUCTORY. — TUB  PARA  I;  rum  it  TREE 
(Ilweti  brasil tennis)  AT  HOME  AND  ABROAD. — CULTIVATION  OF  THE  TREE: — - 
PROPAGATION.  —  SITE  FOR  PLANTATION.  —  DISTANCE  APART  TO  PLANT 
THE  TREES. —  TRANSPLANTING.  -—  CULTIVATION. —  INSECT  PEHTS  AND 
FUNGOID  DISEASES.  —  COLLECTING  THE  RUBBER:  —  VARIOUS  METHODS 
EMPLOYED  IN  TAPPING  RUBBER  TREES. — FLOW  OF  LATEX  INCREASED  BY 
WOUNDING  THE  TREE. — How  TO  TAP. — THE  PREPARATION  OF  RUBBER 
FROM  THE  LATEX: — LATEX. — VARIOUS  METHODS  EMPLOYED  IN  THE  PREP- 
ARATION OF  RUBBER. — SUGGESTED  METHOD  FOR  PREPARING  RUBBER. — 
SCRAP  RUBBER. — YIELD  OF  PARA  RUBBER  FROM  CULTIVATED  TREES. — 
CEYLON. — MALAY  PENINSULA. — GOLD  COAST,  WEST  AFRICA. — ESTABLISH- 
MENT AND  MAINTENANCE  OF  A  PARA  RUBBER  PLANTATION:  —  CEYLON. — 
MALAY  PENINSULA. — COMMERCIAL  VALUE  OF  THE  OIL  IN  HEVEA  SEEDS. 

RUBBER   HAND   STAMPS 

And  the  Manipulation  of  Rubber.  A  Practical  Treatise  on  the  Manu- 
facture of  India-rubber  Hand  Stamps,  Small  Articles  of  India-rubber, 
The  Hektograph,  Special  Inks,  Cements,  and  Allied  Subjects.  By 
T.  O'CoNOR  SLOANE,  A.M.,  Ph.D.  With  numerous  (Illustrations. 
Square  8vq,  cloth.  .  .  SI  .00 

PRACTICAL    PAPER-MAKING. 

A  Manual  for  Paper-Makers  and  Owners  and  Managers  of  Paper-Mills. 
With  Tables,  Calculations,  Ac.  By  G.  CLAPPERTON,  Paper-Maker. 
With  Illustrations  of  Fibres  from  Micro-Photographs.  12mo,  cloth, 

§2.00 

THE   ART   OF   PAPER-MAKING. 

A  Practical  Handbook  of  the  Manufacture  of  Paper  from  Rags,  Esparto 
Straw,  and  other  Fibrous  Materials.  Including  the  Manufacture  of 
Pulp  from  Wood  Fibre,  with  a  Description  of  the  Machinery  and 
Appliances  used.  To  which  are  added  Details  of  Processes  for  Recover- 
ing Soda  from  Waste  Liquors.  By  ALEXANDER  WATT.  With  Illus- 
trations. 12mo,  cloth S3. 00 

A   TREATISE   ON    PAPER. 

For  Printers  and  Stationers.  With  an  Outline  of  Paper  Manufacture; 
Comolete  Tables  of  Sizes,  and  Specimens  of  Different  Kinds  of  Paper. 
By  RICHARD  PARKINSON,  late  of  the  Manchester  Technical  School. 
Demy  8vo,  cloth $1.40 


44        CROSBY  LOCKWOOD  &•>  SON'S  CATALOGUE. 
THE   ART   OF   SOAP=MAKING. 

A  Practical  Handbook  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  &c.  Including  many  new  Processes,  and  a  Chapter  on 
the  Recovery  of  Glycerine  from  Waste  Leys.  By  ALEXANDER  WATT. 
Sixth  Edition,  including  an  Appendix  on  Modern  Candlemaking. 

12mo,  cloth 353.OO 

"A  thoroughly  practical  treatise.  We  congratulate  the  author  on  the 

success  of  his  endeavour  to  fill  a  void  in  English  technical  literature." — 

Nature. 

"The  work  will  prove  very  useful,  not  merely  to  the  technological  student, 
but  to  the  practical  soap  boiler  who  wishes  to  understand  the  theory  of  his 
art." — Chemical  News. 

THE   ART   OF    LEATHER   MANUFACTURE. 

A  Practical  Handbook,  in  which  the  Operations  of  Tanning,  Currying, 
and  Leather  Dressing  are  fully  Described,  and  the  Principles  of  Tanning 
Explained.  Together  witk  a  Description  of  the  Arts  of  Glue  Boiling, 
Gut  Dressing,  &c.  By  ALEXANDER  WATT.  Fifth  Edition,  thoroughly 
Revised  and  Enlarged.  8vo,  cloth Nearly  ready,  $4.00 

ART   OF   BOOT   AND   SHOEMAKING, 

Including  Measurement,  Last-fitting,  Cutting-out,  Closing,  and  Making; 
with  a  Description  of  the  most  Approved  Machinery  employed.  By 

J.  B.  LEND.     12mo,  cloth .80 

"By  far  the  best  work  ever  written  on  the  subject." — Scottish  Leather 
Trader. 

COTTON    MANUFACTURE. 

A  Manual  of  Practical  Instruction  of  the  Processes  of  Opening,  Carding, 
Combing,  Drawing,  Doubling  and  Spinning  of  Cotton,  the  Methods  of 
Dyeing,  &c.  For  the  use  of  Operatives,  Overlookers,  and  Manu- 
facturers. By  JOHN  LISTER,  Technical  Instructor,  Pendleton.  8vo, 
doth $3.00 

"A  distinct  advance  in  the  literature  of  cotton  manufacture." — Machinery 
"It  is  thoroughly  reliable,  fulfilling  nearly  all  the  requirements  desired." 
Glasgow  Herald. 

WATCH    REPAIRING,    CLEANING,    AND    ADJUSTING. 

A  Practical  Handbook  dealing  with  the  Materials  and  Tools  Used  and 
the  Methods  of  Repairing,  Cleaning,  Altering,  and  Adjusting  all  kinds 
of  English  and  Foreign  Watches,  Repeaters,  Chronographs,  and  Marine 
Chronometers.  By  F.  J.  GARRARD,  Springer  and  Adjuster  of  Marine 
Chronometers  and  Deck  Watches  for  the  Admiralty.  With  over  200 
Illustrations.  12mo,  cloth $g .00 

MODERN   HOROLOGY,    IN  THEORY   AND   PRACTICE. 

Translated  from  the  French  of  CLAUDIUS  SAUNIER,  ex-Director  of  the 
School  of  Horology  at  Macon,  by  JULIEN  TRIPPLIN,  F.R.A.S.,  Besancon 
Watch  Manufacturer,  and  EDWARD  RIGG,  M.A.,  Assayer  in  the  Royal 
Mint.  With  Seventy-eight  Woodcuts  and  Twenty-two  Coloured 
Copper  Plates.  Second  Edition.  Super-royal,  8vo,  cloth. . .  .$15.00 
Half-calf $18.00 

THE   WATCHMAKER'S   HANDBOOK. 

Intended  as  a  Workshop  Companion  for  those  engaged  in  Watchmaking 
and    the    Allied    Mechanical    Arts.     Translated    from    the    French    of 
CLAUDIUS  SAUNTER,  and  enlarged  by  JULIEN  TRIPPLIN,  F.R.A.S.,  and 
EDWARD  RIGG,  M.A.,  Assayer  in  the  Royal  Mint.     Fourth  Edition 
12mo,  cloth $3.00 


INDUSTRIAL  AND  USEFUL  ARTS.  45 

CLOCKS,  WATCHES,  &  BELLS  for  PUBLIC  PURPOSES. 

A  Rudimentary  Treatise.  By  EDMUND  BECKETT.  LORD  GKIMTHORPE. 
LL.U.,  K.C.,  F.R.A.S.  Eighth  Edition,  with  new  List  of  Great  Bells 
and  an  Appendix  on  Weathercocks.  12mo,  cloth  .  .  S  1 .  >O 

HISTORY  OF  WATCHES  &  OTHER  TIMEKEEPERS. 

By  JAMES  F.  KENDAL,  M.B.H.Inst.     .00  boards;  or  cloth,  gilt.  81. OO 

ELECTRO-PLATING  &  ELECTRO-REFINING  of  METALS. 

Being  a  new  edition  of  ALEXANDER  WATT'S  "  ELECTRO- I)K POSITION." 
Revised  and  Largely  Rewritten  by  ARNOLD  PHILIP.  B.Sc.,  A.I.E.E., 
Principal  Assistant  to  the  Admiralty  Chemist.  8vo,  cloth  .  84. 5O 

ELECTROPLATING. 

A  Practical  Handbook  on  the  Deposition  of  Copper,  Silver.  Nickel.  Gold, 
Aluminium,  Brass,  Platinum.  Ac..  Ac.  By  J.  W.  URQUHART.  C.E. 
Fifth  Edition,  Revised.  12mo,  cloth .  .  $'^.<)O 

ELECTRO-METALLURGY, 

Practically  Treated.  By  ALEXANDER  WATT.  Tenth  Edition,  enlarged 
and  revised.  With  Additional  Illustrations,  and  including  the  most 
Recent  Processes.  12mo.  cloth SI. 40 

GOLDSMITH'S   HANDBOOK, 

Containing  full  Instructions  in  the  Art  of  Alloying,  Melting,  Reducing, 
Colouring,  Collecting,  and  Refining.  The  Processes  of  Manipulation. 
Recovery  of  Waste,  Chemical  and  Physical  Properties  of  Gold;  Solders, 
Enamels,  and  other  useful  Rules  and  Recipes,  Ac.  By  GEORGE  E. 
GEE.  Sixth  Edition.  12mo,  cloth 81. 2O 

SILVERSMITH'S   HANDBOOK, 

On  the  same  plan  as  the  above.     By  GEORGE  E.  GEE.     Third  Edition. 

12mo,  cloth -81. 2O 

***  The  two  preceding  Warkt,  in  One  handsome  Volume,  half -bound,  en- 
titled "THE  GOLDSMITH'S  AND  SILVERSMITH'S  COMPLETE  HANDBOOK,  "82.8O 

JEWELLER'S  ASSISTANT   IN   WORKING    IN   GOLD. 

A  Practical  Treatise  for  Masters  and  Workmen,  Compiled  from  the 
Experience  of  Thirty  Years'  Workshop  Practice.  By  GEOROE  E.  GEE. 
12mo,  ...  83.00 

HALL-MARKING    OF   JEWELLERY. 

Comprising  an  account  of  all  the  different  Assay  Towns  of  the  United 
Kingdom,  with  the  Stamps  at  present  employed ;  also  the  Laws  relating 
to  the  Standards  and  Hall-marks  at  the  Various  Assay  Offices.  By 
GEORGE  E.  GEE.  12mo,  cloth 81.20 

ELECTROTYPING. 

The  Reproduction  and  Multiplication  of  Printing  Surfaces  and  Works 
of  Art  by  the  Electro- Deposition  of  Metals.  By  J.  W.  URQDHART,  C.E. 
12mo,  cloth 82.OO 

MECHANICAL   DENTISTRY: 

A  Practical  Treatise  on  the  Construction  of  the  Various  Kinds  of 
Artificial  Dentures,  comprising  also  Useful  Formulae,  Tables  and 
Receipts.  By  C.  HUNTER.  12mo,  cloth 81.20 

BRASS   FOUNDER'S   MANUAL: 

Instructions  for  Modelling,  Pattern  Making,  Moulding,  Turning,  Ac. 
By  W.  GRAHAM.  12mo,  cloth .80 


46        CROSBY  LOCKWOOD  &>  SON'S  CATALOGUE 
SHEET   METAL  WORKER'S    INSTRUCTOR. 

Comprising  a  Selection  of  Geometrical  Problems  and  Practical  Rules 
for  Describing  the  Various  Patterns  Required  by  Zinc,  Sheet-Iron, 
Copper,  and  Tin-Plate  Workers.  By  REUBEN  HENRY  WARN.  Piactical 
Tin-Plate  Worker.  New  Edition,  Revised  and  greatly  Enlarged  by 
JOSEPH  G.  HORNER,  A.M.I.M.E.  12mo,  254  pp..  with  430  Illustra- 
tions, cloth §3.00 

SHEET   METALWORKER'S   GUIDE. 

A  Practical  Handbook  for  Tinsmiths,  Coppersmiths,  Zincworkers,  &c  , 
with  46  Diagrams  and  Working  Patterns.  By  W.  J.  E.  CRANE.  Fourth 
Edition.  12mo,  cloth tQQ 

GAS   FITTING: 

A  Practical  Handbook.     By  JOHN  BLACK.     Revised  Edition      With 

130  Illustrations.     12mo,  cloth $1.00 

"It  is  written  in  a  simple,  practical  style,  and  we  heartily  recommend  it." 
— Plumber  and  Decorator. 

TEA   MACHINERY    AND   TEA    FACTORIES. 

A  Descriptive  Treatise  on  the  Mechanical  Appliances  required  in  the 
Cultivation  of  the  Tea  Plant  and  the  Preparation  of  Tea  for  the  Market. 
By  A.  J.  WALLIS-TAYLER,  A.M.Inst.C.E.  Medium  8vo,  468  pp.  With 
218  Illustrations $10.00 

SUMMARY  OF  CONTENTS. 

MECHANICAL  CULTIVATION  OR  TILLAGE  OF  THE  SOIL. — PLUCKING  OR 
GATHERING  THE  LEAF. — TEA  FACTORIES. — THE  DRESSING,  MANUFACTURE, 
OR  PREPARATION  OF  TEA  BY  MECHANICAL  MEANS. — ARTIFICIAL  WITHER- 
ING OF  THE  LEAF. — MACHINES  FOR  ROLLING  OR  CURLING  THE  LEAF. — FER- 
MENTING PROCESS. — MACHINES  FOR  THE  AUTOMATIC  DRYING  OR  FIRING 

OF  THE  LEAF. MACHINES  FOR  NON-AUTOMATIC  DRYING  OR  FIRING  OF  THE 

LEAF. — DRYING  OR  FIRING  MACHINES. — BREAKING  OR  CUTTING,  AND  SORT- 
ING MACHINES. — PACKING  THE  TEA. — MEANS  OF  TRANSPORT  ON  TEA  PLAN- 
TATIONS.— MISCELLANEOUS  MACHINERY  AND  APPARATUS. — FINAL  TREAT- 
MENT OF  THE  TEA. — TABLES  AND  MEMORANDA. 

FLOUR   MANUFACTURE. 

A  Treatise  on  Milling  Science  and  Practice,  By  FRIEDRICH  KICK, 
Imperial  Regie rungsrath,  Professor  of  Mechanical  Technology  in  the 
Imperial  German  Polytechnic  Institute,  Prague.  Translated  from  the 
Second  Enlarged  and  Revised  Edition.  By  H.  H.  P.  POWLES,  A.M. 
Inst.C.E.  400  pp.,  with  28  Folding  Plates,  and  167  Woodcuts.  Royal 
8vo,  cloth $10.00 

ORNAMENTAL  CONFECTIONERY. 

A  Guide  for  Bakers,  Confectioners  and  Pastrycooks;  including  a 
variety  of  Modern  Recipes,  and  Remarks  on-  Decorative  and  Coloured 
Work.  With  129  Original  Designs.  By  ROBERT  WELLS.  12mo,  cloth, 

$2.00 

BREAD    &    BISCUIT    BAKER'S    &    SUGAR-BOILER'S 

ASSISTANT. 

Including  a  large  variety  of  Modern  Recipes.  With  Remarks  on  the 
Art  of  Bread-making.  By  ROBERT  WELLS.  Fourth  Edition.  12mo, 
cloth .50 

PASTRYCOOK   &   CONFECTIONER'S   GUIDE. 

For  Hotels,  Restaurants,  and  the  Trade  in  general,  adapted  also  for 
Family  Use.  By  R.  WELLS,  Author  of  "The  Bread  and  Biscuit  Baker." 

,40 


INDUSTRIAL  AND  USEFUL  ARTS.  47 

MODERN    FLOUR   CONFECTIONER. 

Containing  a  large  Collection  of  Recipes  for  ('heap  Cakes.  Biscuits,  «tc. 
With  remarks  on  the  Ingredients  Used  in  their  Manufacture.  By  R. 
WKLLS .  .  .40 

SAVOURIES   AND   SWEETS 

Suitable  for  Luncheons  and  Dinners.  By  Miss  M.  L.  ALLKN  (Mrs.  A. 
MACAIRE),  Author  of  "Breakfast  Dishes,"  Ac.  Thirtieth  Edition.  F'cap 
8vo,  sewed.  .  .40 

BREAKFAST    DISHES 

For  Every  Morning  of  Three  Months.  By  Miss  AI.I.KN  (Mrs.  A. 
MACAIRB),  Author  of  "Savouries  and  Sweets."  Ac.  Twenty  second 
Kdition.  F'cap  8vo,  sewed.  .  .  .40 

MOTOR  CARS  OR  POWER  CARRIAGES  FOR  COMMON 

ROADS. 
By  A.  J.  WALLIS-TAYLKR,  A.M.Inst.C.E.     12rno.  cloth 81. HO 

FRENCH    POLISHING    AND    ENAMELLING. 

A  Practical  Book  of  Instruction,  including  numerous  Recipes  from  mak- 
ing Polishes,  Varnishes,  Glaze  Lacquers,  Revivers,  Ac.  By  R.  BIT- 
MKAD.  12mo,  cloth. .  .  .(JO 

CEMENTS,    PASTES,   GLUES,    AND   GUMS. 

A  Guide  to  the  Manufacture  and  Application  of  Agglutinants  for 
Workshop,  Laboratory,  or  Office  Use.  With  900  Recipes  and  Formula*. 
By  H.  C.  STANDAOK.  Crown  8vo,  cloth .HO 

PRACTICAL   ORGAN    BUILDING. 

By  W.  E.  DICKSON.  M.A.,  Precentor  of  Ely  Cathedral.  Second  Edition, 
Revised.  12mo,  cloth.  ..  81.0O 

COACH-BUILDING: 

A  Practical  Treatise,  Historical  and  Descriptive.  By.  J.  W.  BURGESS. 
12mo,  cloth.  ..  SI.  no 

SEWING   MACHINERY. 

Construction,  History,  Adjusting,  <tc.  By  J.  W.  URQUHAHT.  12mo, 
cloth.  .  .80 

WOOD    ENGRAVING: 

A  Practical  and  Easy  Introduction  to  the  Study  of  the  Art.  By  W.  N. 
BROWN.  12mo,  cloth .60 

LAUNDRY   MANAGEMENT. 

A  Handbook  for  Use  in  Private  and  Public  Laundries.     12mo,  cloth 

.80 

CONSTRUCTION   OF   DOOR   LOCKS. 

From  the  Papers  of  A.  C.  HOBBS.  Edited  by  CHARLES  TOMLINSON, 
F.R.S.  With  a  Note  upon  IRON  SAFES  by  ROBERT  MALLET.  12mo, 
cloth $1.00 


48       CROSBY  LOCKWOOD  &-  SON'S  CATALOGUE. 
HANDYBOOKS  FOR  HANDICRAFTS. 

BY  PAUL  N.  HASLUCK, 
Author  of  "Lathe  Work,"  &c.     12mo,  144  pp.,  price  5Oc.  each. 


These  HANDYBOOKS  have  been  written  to  supply  information  for  WORK- 
MEN, STUDENTS,  and  AMATEURS  in  the  several  Handicrafts,  on  the  actual 
PRACTICE  of  the  WORKSHOP,  and  are  intended  to  convey  in  plain  language 
TECHNICAL  KNOWLEDGE  of  the  several  CRAFTS.  In  describing  the  processes 
employed,  and  the  manipulation  of  material,  workshop  terms  are  used;  work- 
shop practice  is  fully  explained;  and  the  text  is  freely  illustrated  with  drawings 
of  modern  tools,  appliances,  and  processes. 


METAL  TURNER'S  HANDYBOOK. 

A  Practical  Manual  for  Workers  at  the  Foot-Lathe.  With  100  Illus- 
trations   ,50 

WOOD   TURNER'S   HANDYBOOK. 

A  Practical  Manual  for  Workers  at  the  Lathe.  With  over  100  Illus- 
trations   ,50 

WATCH    JOBBER'S   HANDYBOOK. 

A  Practical  Manual  on  Cleaning,  Repairing,  and  Adjusting.  With 
upwards  of  100  Illustrations - .59 

PATTERN    MAKER'S   HANDYBOOK. 

A  Practical  Manual  on  the  Construction  of  Patterns  for  Founders. 
With  upwards  of  100  Illustrations .50 

MECHANIC'S   WORKSHOP   HANDYBOOK. 

A  Practical  Manual  on  Mechanical  Manipulation,  embracing  Informa- 
tion on  various  Handicraft  Processes.  With  Useful  Notes  and  Mis- 
cellaneous Memoranda.  Comprising  about  200  Subjects .50 

MODEL    ENGINEER'S   HANDYBOOK. 

A  Practical  Manual  on  the  Construction  of  Model  Steam  •  Engines. 
With  upwards  of  100  Illustrations .50 

CLOCK   JOBBER'S   HANDYBOOK. 

A  Practical  Manual  on  Cleaning,  Repairing,  and  Adjusting.  With 
upwards  of  100  Illustrations 50 

CABINET   WORKER'S   HANDYBOOK. 

A  Practical  Manual  on  the  Tools,  Materials,  Appliances,  and  Processes 
employed  in  Cabinet  Work.  With  upwards  of  100  Illustrations.  .50 

"Mr.  Hasluck's  thorough-going  little  Handybook  is  amongst  the  most 
practical  guides  we  have  seen  for  beginners  in  cabinet-work." — Saturday 
Review. 

WOODWORKER'S   HANDYBOOK. 

Embracing  Information  on  the  Tools,  Materials,  Appliances,  and 
Processes  Employed  in  Woodworking.  With  104  Illustrations.  .50 


COMMERCE,  COUNTING-HOUSE  WORK,  cr>c.         49 


COMMERCE,    COUNTING-HOUSE    WORK, 
TABLES,   ETC. 


LESSONS    IN    COMMERCE. 

By  Professor  R.  GAMBARO.  of  the  Royal  High  Commercial  School  at 
Genoa.  Edited  and  Revised  by  JAMES  GAULT,  Professor  of  Commerce 
and  Commercial  Law  in  King's  College.  London.  Fifth  Edition. 
12mo,  cloth.  . .  £1.40 

THE   FOREIGN   COMMERCIAL  CORRESPONDENT. 

Being  Aids  to  Commercial  Correspondence  in  Five  Language* — English. 
French,  German.  Italian,  and  Spanish.  By  CONRAD  E.  BAKKR.  Third 
Edition,  Carefully  Revised  Throughout.  12mo.  cloth $}  £O 


FACTORY  ACCOUNTS:  their  PRINCIPLES  &  PRACTICE. 

A  Handbook  for  Accountants  and  Manufacturers,  with  Appendices  on 
the  Nomenclature  of  Machine  Details;  the  Income  Tax  Acts*  the 
Ratine  of  Factories;  Fire  and  Boiler  Insurance;  the  Factory  and  Work- 
shop Acts.  Ac.,  including  also  a  Glossary  of  Terms  and  a  large  number 
of  Specimen  Rulings.  By  EMILB  GARCKE  and  J.  M.  FELLS.  Fifth 
Edition.  Revised  and  Enlarged.  Demy  8vo,  cloth 83.00 


MODERN    METROLOGY. 

A  Manual  of  the  Metrical  Units  and  Systems  of  the  present  Century- 
With  an  Appendix  'containing  a  proposed  English  System.  By 
Lowis  n'A-  JACKSON,  A.M  Inst.C.E..  Author  of  "Aid  to  Survey  Prac- 
tice," <kc.  8vo,  cloth 35.0O 


A   SERIES  OF    METRIC   TABLES. 

In  which  the  British  Standard  Measures  and  Weights  are  compared 
with  those  of  the  Metric  System  at  present  in  Use  on  the  Continent. 
By  C.  H.  DOWLINO,  C.E.  8vo,  cloth $4.00 


IRON-PLATE   WEIGHT   TABLES. 

For  Iron  Shipbuilders,  Engineers,  and  Iron  Merchants  Containing  the 
Calculated  Weights  of  upwards  of  150,000  different  siies  of  Iron  Plates 
from  1  foot  by  6  in.  by  i  in.  to  10  feet  by  5  feet  by  1  in.  Worked  out 
on  the  Basis  of  40  Ibs.  to  the  square  foot  of  Iron  ot  1  inch  in  thickness. 
By  H,  BURUNSON  and  W.  H.  SIMPSON.  4to,  half-bound $10.00 


50        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 

AGRICULTURE,   FARMING, 
GARDENING,   ETC. 


THE    COMPLETE    GRAZIER    AND    FARMER'S    AND 

CATTLE   BREEDER'S  ASSISTANT. 

A  Compendium  of  Husbandry.  Originally  Written  by  WILLIAM 
You  ATT.  Fourteenth  Edition,  entirely  Re-  written,  considerably  En- 
larged, and  brought  up  to  Present  Requirements,  by  WILLIAM  IREAM, 
LL.D.,  Assistant  Commissioner,  Royal  Commission  on  Agriculture, 
Author  of  "The  Elements  of  Agriculture,"  &c.  Royal,  8vo,  1,100  pp., 
450  Illustrations,  handsomely  bound 


STOCK:   CATTLE,    SHEEP,    AND    HORSES. 

Vol.  III.—  OUTLINES  OF  MODERN  FARMING.  By  R.  SCOTT  BURN. 
Woodcuts.  12mo,  cloth  ..................................  $1.00 

SHEEP: 

The  History,  Structure,  Economy,  and  Diseases  of.  By  W.  C.  SPCONER. 
Fifth  Edition,  with  Engravings,  including  Specimens  of  New  and 
Improved  Breeds.  12mo,  cloth  ............................  SI.  40 

MEAT   PRODUCTION: 

A  Manual  for  Producers,  Distributors,  and  Consumers  of  Butchers' 
Meat.  By  JOHN  EWART.  12mo,  cloth  .....................  $1.00 

MILK,  CHEESE,  AND  BUTTER. 

A  Practical  Handbook  on  their  Properties  and  the  Processes  of  their 
Production.  Including  a  Chapter  on  Cream  and  the  Methods  of  its 
Separation  from  Milk.  By  JOHN  OLIVER,  late  Principal  of  the  Western 
Dairy  Institute,  Berkeley.  With  Coloured  Plates  and  200  Illustra- 
tions. 12mo,  cloth  ..........  ............................  $3.00 

BRITISH    DAIRYING. 

A  Handy  Volume  on  the  Work  of  the  Dairy-Farm.  For  the  Use  of 
Technical  Instruction  Classes,  Students  in  Agricultural  Colleges  and 
the  Working  Dairy-Farmer.  By  Prof.  J.  P.  SHELDON.  With  Illus- 
trations. Second  Edition,  Revised.  12mo,  cloth  .......  .....  $1.00 

DAIRY,    PIGS,    AND    POULTRY. 

Vol.  IV.  OUTLINES  OF  MODERN  FARMING.  By  R.  SCOTT 
BURN.  Woodcuts.  12mo,  cloth  ..........................  .80 

THE    ELEMENTS   OF   AGRICULTURAL   GEOLOGY. 

A  Scientific  Aid  to  Practical  Farming.  By  PRIMROSE  MCCONNELL. 
Author  of  "Note-book  of  Agricultural  Facts  and  Figures."  8vo,  cloth, 

$7.50 
SOILS,    MANURES,    AND   CROPS. 

Vol.  I.—  OUTLINES  OF  MODERN  FARMING.  By  R.  SCOTT  BURN. 
Woodcuts.  12mo,  cloth  ..................................  .80 

FERTILISERS   AND    FEEDING    STUFFS. 

Their  Properties  and  Uses.  A  Handbook  for  the  Practical  Farmer. 
By  BERNARD  DYER,  D.Sc.  (Lond.)  With  the  Text  of  the  Fertilisers 
and  Feeding  Stuffs  Act  of  1893,  The  Regulations  and  Forms  of  the 
Board  of  Agriculture,  and  Notes  on  the  Act  by  A.  J.  DAVID,  B.A., 
LL.M.  Fourth  Edition,  Revised.  12mo,  cloth  ..............  .40 

THE     ROTHAMSTED     EXPERIMENTS     AND     THEIR 

PRACTICAL  LESSONS   FOR   FARMERS. 

Part  I.     STOCK.     Part  II.  CROPS.     By  C.  J.  R.  TIPPER.     12mo,  cloth 


AGRICULTURE,  FARMING,  GARDENING,  &c.   51 
SYSTEMATIC   SMALL    FARMING. 

Or,  The  Lessons  of  My  Farm.  Being  an  Introduction  to  M<Klern  Farm 
Practice  for  Small  Farmers.  By  R.  SCOTT  BURN,  Author  of  "Outlines 
of  Modern  Farming,"  Ac.  12mo,  cloth $'<£.4O 

THE    FIELDS   OF   GREAT   BRITAIN. 

A  Text-Book  of  Agriculture.  Adapted  to  the  Syllabus  of  the  Science 
and  Art  Department.  For  Elementary  and  Advanced  Students.  By 
HUGH  CI.KMKN-TS  (Board  of  Trade).  Second  Edition,  Revised,  with 
Additions.  18mo,  cloth 81  .(H) 

OUTLINES   OF   MODERN    FARMING. 

By  R.  SCOTT  BURN.  Soils,  Manures,  and  Crops — Farming  and  Farming 
Economy — Cattle,  Sheep,  and  Horses — Management  of  Dairy,  Pigs, 
and  Poultry — Utilisation  of  Town-Sewage,  Irrigation,  Ac.  Sixth 
Edition.  In  One  Vol.,  1,250  pp.,  half-bound,  profusely  Illustrated. 

•4.80 

FARM  ENGINEERING,  The  COMPLETE  TEXT-BOOK  of. 

Comprising  Draining  and  Embanking;  Irrigation  and  Water  Supply; 
Farm  Roads,  Fences  and  Gates;  Farm  Buildings;  Barn  Implements 
and  Machines-  Field  Implements  and  Machines;  Agricultural  Survey- 
ing, Ac.  By  Professor  JOHN  SCOTT.  1,150  pp.,  half  -bound,  with  over 
GOO  Illustrations S4.HO 

DRAINING    AND    EMBANKING. 

A  Practical  Treatise.  By  JOHN  SCOTT,  late  Professor  of  Agriculture 
and  Rural  Economy  at  the  Royal  Agricultural  College,  Cirencester. 
With  68  Illustrations.  12mo,  cloth. .  .  .(JO 

"A  valuable  handbook  to  the  engineer  as  well  as  to  the  surveyor." — Land. 

IRRIGATION   AND   WATER   SUPPLY: 

A  Practical  Treatise  on  Water  Meadows,  Sewage  Irrigation,  Warping, 
Ac.:  on  the  Construction  of  Wells,  Ponds,  and  Reservoirs,  Ac.  By 
Professor  J.  SCOTT.  12mo,  cloth i  ,o 

FARM  ROADS,  FENCES,  AND  GATES: 

A  Practical  Treatise  'on  the  Roads.  Tramways,  and  Waterways  of  the 
Farm;  the  Principles  of  Enclosures*  and  on  Fences,  Gates,  and  Stiles. 
By  Professor  JOHN  SCOTT.  12mo,  cloth .04) 

BARN    IMPLEMENTS   AND   MACHINES: 

Treating  of  the  Application  of  Power  to  the  Operations  of  Agriculture 
and  of  the  various  Machines  used  in  the  Threshing-barn,  in  the  Stock- 
yard, Dairy,  Ac.  By  Professor  JOHN  SCOTT.  With  123  Illustrations. 
12mo,  cloth 8O 

FIELD    IMPLEMENTS   AND   MACHINES: 

With  Principles  and  Details  of  Construction  and  Points  of  Excellence, 
their  Management,  Ac.  By  Professor  JOHN  SCOTT.  With  138  Illus- 
trations. 12mo,  cloth 8O 

AGRICULTURAL   SURVEYING. 

A  Treatise  on  Land  Surveying,  Levelling,  and  Setting-out;  with  Direc- 
tions for  Valuing  and  Reporting  on  Farms  and  Estates.  By  Professor 
J.SCOTT.  12mo,  cloth .60 

OUTLINES  OF   FARM    MANAGEMENT. 

Treating  of  the  General  Work  of  the  Farm;  Stock;  Contract  Work, 
Labour,  Ac.  By  R.  SCOTT  BURN.  12mo, cloth Sl.(H) 

OUTLINES  OF   LANDED   ESTATES   MANAGEMENT. 

Treating  of  the  Varieties  of  Lands,  Methods  of  Farming,  the  Setting-out 
of  Farms,  Ac.;  Roads,  Fences,  Gates,  Irrigation.  Drainage,  Ac.  By 
R.  S.  BURN.  12mo,  cloth 81.OO 


S2        CROSBY  LOCKWOOD  &  SON'S  CATALOGUE. 
FARMING    AND    FARMING    ECONOMY. 

Historical  and  Practical.  Vol.  II.— OUTLINES  OF  MODERN 
FARMING.  By  R.  SCOTT  BURN.  12mo,  cloth $1.20 

UTILIZATION    OF   SEWAGE,    IRRIGATION,    &c. 

Vol.  V.— OUTLINES  OF  MODERN  FARMING.  By  R.  SCOTT  BURN. 
Woodcuts.  12mo,  cloth Sl.OO 

NOTE-BOOK  OF  AGRICULTURAL  FACTS  &  FIGURES 

FOR   FARMERS   AND   FARM   STUDENTS. 

By  PRIMROSE  MCDONNELL,  B.Sc.,  Fellow  of  the  Highland  and  Agri- 
cultural Society,  Author  of  "Elements  of  Farming."  Seventh  Edition, 
Re-written,  Revised,  and  greatly  Enlarged.  Fcap.  8vo,  480  pp., 
leather,  gilt  edges [Just  Published.  $3.u <J 

TABLES  and  MEMORANDA  for  FARMERS,  GRAZIER?, 

AGRICULTURAL     STUDENTS,     SURVEYORS,     LAND     AGENTS, 
AUCTIONEERS,    &c. 

With  a  New  System  of  Farm  Book-keeping.  By  SIDNEY  FRANCIS. 
Fifth  Edition.  272  pp.,  waistcoat-pocket  size,  limp  leather.  .  .  .60 

THE   HAY   AND   STRAW    MEASURER: 

New  Tables  for  the  Use  of  Auctioneers,  Valuers,  Farmers,  Hay  and 
Straw  Dealers,  &c.,  forming  a  complete  Calculator  and  Ready  Reck- 
oner. By  JOHN  STEELE.  12mo,  cloth .£0 

READY  RECKONER  FOR  ADMEASUREMENT  OF  LAND. 

By  A.  ARM  AN.  Revised  and  extended  by  C.  NORRIS,  Surveyor.  Fifth 
Edition.  12mo,  cloth .80 

THE   HORTICULTURAL   NOTE=BOOK. 

A  Manual  of  Practical  Rules,  Data,  and  Tables,  for  the  use  of  Students, 
Gardeners,  Nurserymen,  and  others  interested  in  Flower,  Fruit,  and 
Vegetable  Culture,  or  in  the  Laying-out  and  Management  of  Gardens. 
By  J.  C.  NewsHAM,  F.R.H.S.,  Headmaster  of  the  Hampshire  County 
Council  Horticultural  School.  With  numerous  Illustrations.  Fcap. 
8vo,  cloth [Just  Published.  $3.00 

MARKET   AND    KITCHEN    GARDENING. 

By  C.  W.  SHAW,  late  Editor  of  "Gardening  Illustrated."     Crown  8vo, 

$1.40 
A   PLAIN   GUIDE   TO   GOOD   GARDENING; 

Or,  How  to  Grow  Vegetables,  Fruits,  and  Flowers.  By  S.  WOOD. 
Fourth  Edition,  with  considerable  Additions,  and  numerous  Illustra- 
tions. 12mo,  cloth $1.40 

THE   FORCING   GARDEN; 

Or,  How  to  Grow  Early  Fruits,  Flowers  and  Vegetables.  With  Plans 
and  Estimates  for  Building  Glasshouses,  Pits  and  Frames.  With 
Illustrations.  BySAMUEL  WOOD.  12mo,  cloth $1.40 

KITCHEN   GARDENING   MADE    EASY. 

Showing  the  best  means  of  Cultivating  every  known  Vegetable  and 
Herb,  <fec.,  with  directions  for  management  all  the  year  round.  By 
GEO.  M.  F.  GLENNY.  Illustrated.  12mo,  cloth .60 

COTTAGE   GARDENING; 

Or,  Flowers,  Fruits,  and  Vegetables  for  Small  Gardens.  By  E.  HOBDAY. 
12mo,  cloth .60 

GARDEN    RECEIPTS. 

Edited  by  CHARLES  W.  QUIN.     Fourth  Edition.     12mo,  cloth,       .60 

MULTUM-IN-PARVO   GARDENING; 

Or,  How  to  Make  One  Acre  of  Land  produce  S3OO7  a  year,  by  the 
Cultivation  of  Fruits  and  Vegetables;  also,  How  to  Grow  Flowers  in 
Three  Glass  Houses,  so  as  to  realise  S853.6O  per  annum  clear  Profit. 
By  SAMUEL  WOOD,  Author  of  "Good  Gardening,"  &c.  Sixth  Edition. 
12mo,  paper .50 


AGRICULTURE,  FARMING,  GARDENINR,  6-c.       53 
THE  LADIES'  MULTUM-IN-PARVO  FLOWER  GARDEN. 

And  Amateur's  Complete  Guide.     By  S.  WOOD.     12mo,  cloth,  SI. 40 

FRUIT   TREES, 

The  Scientific  and  Profitable  Culture  of.  From  the  French  of  M.  Du 
BRKUIL.  Fifth  Edition,  carefully  Revised  by  GEORGE  GLENNY.  With 
187  Woodcuts.  12nao,  cloth SI  .40 

ART   OF   GRAFTING   AND   BUDDING. 

By  CHARLES  BALTET.     With  Illustrations.     12mo,  cloth.  .         SI  .()i) 

TREE    PRUNER: 

Being  a  Practical  Manual  on  the  Pruning  of  Fruit  Trees,  including  also 
their  Training  and  Renovation,  also  treating  of  the  Pruning  of  Shrub-. 
Climbers,  and  Flowering  Plants.  With  numerous  Illustrations.  By 
SAMUEL  WOOD,  Author  of  "Good  Gardening,"  Ac.  12mo,  cloth.  .(JO 

TREE  PLANTER  AND  PLANT  PROPAGATOR: 

With  numerous   Illustrations  of  Grafting,  Layering,  Budding,  Imple- 
ments, Houses,  Pits.  Ac.     By  S.  WOOD.     12mo,  cloth  .HO 
"  Sound  in  its  teaching  and  very  comprehensive  in  its  aim.    It  is  a  good 
book." — Gardeners'  Magazine. 

***  The  above  Two  Volt,  in  One,  handsomely  half-bound,  entitled  "THE 
TREE  PLANTER,  PROPAOATOR  AND  PRUNKR."  By  SAMUEL  WOOD. 

SI. 40 

THE   CULTIVATION   AND   PREPARATION    OF    PARA 

RUBBER. 

By  W.  H.  JOHNSON,  F.L.S.,  F.R.H.S.     8vo,  cloth Net  S3.00 

For  Summary  of  Contents,  see  page  43. 

BEES   FOR   PLEASURE   AND   PROFIT. 

A  Guide  to  the  Manipulation  of  Bees,  the  Production  of  Honey,  and  the 
General  Management  of  the  Apiary.  By  G.  GORDON  SAMSON.  With 
numerous  Illustrations.  12mo,  wrapper .40 


MATHEMATICS,  ARITHMETIC,  ETC. 


TREATISE   ON   MATHEMATICS, 

As  applied  to  the  Constructive  Arts.  By  FRANCIS  CAMPIN,  C.E.,  Ac. 
Third  Edition.  12mo,  cloth. .  .  .S  1  .?O 

SLIDE    RULE,   AND   HOW   TO   USE   IT. 

Containing  full,  easy,  and  simple  Instructions  to  perform  all  Business 
Calculations  with  unexampled  rapidity  and  accuracy.  By  CHARLES 
HOARK,  C.E.  With  a  Slide  Rule,  in  tuck  of  cover.  Eighth  Edition. 
12mo.  ....  Sl.OO 

MATHEMATICAL   TABLES, 

For  Trigonometrical,  Astronomical,  and  Nautical  Calculations;  to 
which  is  prefixed  a  Treatise  on  Logarithms.  By  H.  LAW,  C.E.  To- 
gether with  a  Series  of  Tables  for  Navigation  and  Nautical  Astronomy. 
By  Professor  J.  R.  YOUNO.  New  Edition.  12mo,  cloth S1.6O 

LOGARITHMS. 

With  Mathematical  Tables  for  Trigonometrical,  Astronomical,  and 
Nautical  Calculations.  By  HENRY  LAW,  C.E.  Revised  Edition. 
(Forming  part  of  the  preceding  work.)  12mo,  cloth S1.20 


54        CROSBY  LOCKWOOD  &»  SON'S  CATALOGUE. 
EUCLID, 

The  Elements  of;  with  many  Additional  Propositions  and  Explanatory 
Notes;  to  which  is  prefixed  an  Introductory  Essay  on  Logic.  By 

HENRY  LAW,  C.E.     12mo,  cloth ajl.UO 

***  Sold  also  separately,  viz.: — 

EUCLID.     The  First  Three  Books.     By  HENRY  LAW,  C.E.     Crown  8vo, 
cloth. 4^jO 

EUCLID.     Books  4,  5,  6,  11,  12.     By  HENRY  LAW,  C.E.     Crown  8vo 
c^th .60 

THEORY  OF  COMPOUND  INTEREST  AND  ANNUITIES, 

With  Tables  of  Logarithms  for  the  more  Difficult  Computations  of 
Interest,  Discount,  Annuities,  &c.,  in  all  their  Applications  and  Uses 
for  Mercantile  and  State  Purposes.  By  FEDOR  THOMAN,  of  the  Societe 
Credit  Mobilier,  Paris.  Fourth  Edition.  12mo,  cloth &1.6O 

ARITHMETIC, 

Rudimentary,  for  the  Use  of  Schools  and  Self-Instruction.  By  JAMES 
HADDON,  M.A.  Revised  by  ABRAHAM  ARMAN.  12mo,  cloth..  .60 

ARITHMETIC, 

A  Rudimentary  Treatise  on:  with  full  Explanations  of  its  Theoretical 
Principles,  and  numerous  Examples  for  Practice.  For  the  use  of 
Schools  and  for  Self-Instruction.  By  J.  R.  YOUNG,  late  Professor  of 
Mathematics  in  Belfast  College.  14th  Ed.  12mo,  cloth .60 

KEY   TO   THE   ABOVE. 

By  J.  R.  YOUNG.     12mo,  cloth .60 

EQUATIONAL   ARITHMETIC, 

Applied  to  Questions  of  Interest,  Annuities,  Life  Assurance ,  and  General 
Commerce:  with  various  Tables  by  which  all  calculations  may  be 
greatly  facilitated.  By  W.  HIPSLEY.  12mo,  cloth ,6O 

COMMERCIAL   BOOK=KEEPINQ. 

With  Commercial  Phrases  and  Forms  in  English,  French,  Italian,  and 
German.  By  JAMES  HADDON,  M.A.,  formerly  Mathematical  Master, 
King's  College  School.  12mo,  cloth .60 

ALGEBRA, 

The  Elements  of.  By  JAMES  HADDON,  M.A.,  formerly  Mathematical 
Master  of  King's  College  School.  With  Appendix,  containing  Mis- 
cellaneous Investigations,  and  a  collection  of  Problems.  12mo,  cloth, 

.80 

KEY  AND  COMPANION  TO  THE  ABOVE, 

An  extensive  repository  of  Solved  Examples  and  Problems  in  Illustra- 
tion of  the  various  Expedients  necessary  in  Algebraical  Operations. 
By  J.  R.  YOUNG.  12mo,  cloth 60 

DESCRIPTIVE   GEOMETRY, 

An  elementary  Treatise  on;  with  a  Theory  of  Shadows  and  of  Per- 
spective extracted  from  the  French  of  G.  MONGE.  To  which  is  added 
a  Description  of  the  Principles  and  Practice  of  Isometrical  Projection. 
By  J.  F.  HEATHER,  M.A.  With  14  Plates.  12mo,  cloth 80 

PRACTICAL    PLANE   GEOMETRY: 

Giving  the  Simplest  Modes  of  Constructing  Figures  contained  in  one 
Plane  and  Geometrical  Constructions  of  the  Ground.  By  J.  F.  HEATHER, 
M.A.  12mo,  cloth SO 


MATHEMATICS,  ARITHMETIC,  ^c.  55 

ANALTYICAL   GEOMETRY    AND   CONIC    SECTIONS. 

By  J.  HANN.     Enlarged  by  Professor  J.  R.  YOUNG.     Crown  8vo,  cloth 

.80 

PLANE   TRIGONOMETRY, 

The  Elements  of.     By  JAMES  HANN,  M.A.     Seventh  Edition.     12mo 

.60 

SPHERICAL   TRIGONOMETRY, 

The  Elements  of.  By  JAMES  HANN.  Revised  by  CHARLES  H.  DOW- 
LING,  C.E.  12mo,  cloth .  ,  j 

*»*  Or  with  "The  Element*  of  Plane  Trigonometry"  in  One  Vol      Crown 
8vo,  cloth 81. OJ 

DIFFERENTIAL   CALCULUS, 

Elements  of  the.     By  W.  S.  B.  WOOLHOCSE.     12mo,  cloth. ...       .60 

INTEGRAL  CALCULUS. 

By  HOMERSHAM  Cox,  B.A.     12mo,  cloth .60 

MATHEMATICAL    INSTRUMENTS, 

A  Treatise  on;  Their  Construction,  Adjustment,  Testing,  and  Use  con. 
cisely  explained.  By  J.  F.  HEATHER,  M.A.,  of  the  Royal  Military 
Academy,  Woolwich.  Fifteenth  Edition,  Revised  with  Additions,  by 
A.  T.  WAI.MISLKY,  M.Inst.C.E..  Fellow  of  the  Surveyors'  Institution. 
Original  Edition  in  One  Vol.,  Illustrated.  12mo,  cloth .so 

%*  In  ordering  be  careful  to  say  "Original  Edition"  to  distinguish  it  from  the 
Enlarged  Edition  in  Three  VoU  (tee  below). 

DRAWING    AND   MEASURING    INSTRUMENTS. 

Including — I.  Instruments  employed  in  Geometrical  and  Mechanical 
Drawing,  and  in  the  Construction,  Copying,  and  Measurement  of  Maps 
and  Plans.  II.  Instruments  used  for  the  purposes  of  Accurate  Measure- 
ment, and  for  Arithmetical  Computations.  By  J.  F.  HEATHER,  M.A. 
12mo .60 

OPTICAL   INSTRUMENTS. 

Including  (more  especially)  Telescopes,  Microscopes,  and  Apparatus  for 
producing  copies  of  Maps  and  Plans  by  Photography.  By  J.  F. 
HEATHER,  M.A.  Illustrated.  12mo,  cloth .60 

SURVEYING    AND   ASTRONOMICAL    INSTRUMENTS. 

Including — I.  Instruments  used  for  Determining  the  Geometrical 
Features  of  a  portion  of  Ground.  II.  Instruments  employed  in 
Astronomical  Observations.  By  J.  F.  HEATHER,  M.A.  Illustrated. 
12mo,  cloth ...  .6^ 

%*  The  above  Three  Volumes  form  an  Enlargement  of  the  Author' t  original 
work,  "Mathematical  Instruments,"  price  .80. 

MATHEMATICAL    INSTRUMENTS: 

Their  Construction,  Adjustment,  Testing,  and  Use.  Comprising  Draw- 
ing, Measuring,  Optical,  Surveying,  and  Astronomical  Instruments. 
By  J.  F.  HEATHER,  M.A.  Enlarged  Edition,  for  the  most  part  re- 
written. Three  parts  as  above.  12mo,  cloth S1.8O 

STATICS    AND    DYNAMICS, 

The  Principles  and  Practice  of;  embracing  also  a  clear  development  of 
Hvdrostatics,  Hydrodynamics,  and  Central  Forces.  By  T.  BAKER, 
C.E.  Fourth  Edition.  12mo,  cloth .60 


56        CROSBY  LOCKWOOD  &•  SON'S  CATALOGUE. 
LAW    AND    MISCELLANEOUS. 


PATENTS  for  INVENTIONS,  HOW  to  PROCURE  THEM. 

Compiled  for  the  Use  of  Inventors,  Patentees  and  others.  By  G.  G.  M. 
HARDINGHAM,  Assoc.  Mem.  Inst.  C.E.,  &c.  Demy  8vo,  cloth,  .60 

DICTIONARY   OF    PAINTERS, 

And  Handbook  for  Picture  Amateurs;  being  a  Guide  for  Visitors  to 
Public  and  Private  Picture  Galleries,  and  for  Art  Students  including 
Glossary  of  Terms,  &c.  By  PHILIPPE  DARYL,  B. A.  12mo,  cloth.  $1.OU 

DICTIONARY  OF  TERMS  USED   IN   ARCHITECTURE. 

Building  Engineering,  Mining,  Metallurgy,  Archaeology,  the  Fine  Arts, 
&c.  By  JOHN  WEALE.  Sixth  Edition.  Edited  by  ROBT.  HUNT, 
F.R.S.  Numerous  Illustrations,  12mo,  cloth $#.00 

NATURAL   PHILOSOPHY, 

For  the  Use  of  Beginners.     By  C.  TOMLINSON,  F.R.S.     12mo,  cloth 

.60 
HANDBOOK   OF   FIELD   FORTIFICATION. 

By  Major  W.  W.  KNOLLYS,  F.R.G.S.     12mo,  cloth $1.20 

COMPENDIOUS   CALCULATOR 

(Intuitive  Calculations};  or  Easy  and  Concise  Methods  of  performing  the 
various  Arithmetical  Operations  required  in  Commercial  and  Business 
Transactions ;  together  with  Useful  Tables,  &c.  By  DANIEL  O'GORMAN. 
Twenty-eighth  Edition,  revised.by  C.  NORRIS.  12mo,  cloth..  -5§1.00 

MEASURES,     WEIGHTS,      AND     MONEYS     OF     ALL 

NATIONS. 

And  an  Analysis  of  the  Christian,  Hebrew,  and  Mahometan  Calendars. 
By  W.  S.  B.  WOOLHOUSE,  F.R.A.S.  7th  Ed.  12mo,  cloth.  {&1.OO 

SPANISH   GRAMMAR. 

In  a  Simple  and  Practical  Form.  With  Exercises.  By  ALFRED  ELWES. 
12mo,  cloth .60 

SPANISH-ENGLISH      AND      ENGLISH-SPANISH      DIC- 
TIONARY. 

Including  a  large  number  of  Technical  Terms  used  in  Mining,  Engineer- 
ing, &c.,  with  the  proper  Accents  and  the  Gender  of  every  Noun.  By 
ALFRED  ELWES.  12mo,  cloth <gl  .60 

PORTUGUESE   GRAMMAR. 

In  a  Simple  and  Practical  Form.  With  Exercises.  By  ALFRED 
ELWES.  12mo,  cloth .60 

PORTUGUESE=ENGLISH        AND        ENGLISH=PORTU- 

GUESE   DICTIONARY. 

Including  a  large  r 
ing,  &c.,  with  the 
ALFRED  ELWES. 

ANIMAL   PHYSICS. 

Handbook  of.  By  DIONYSIUS  LARHNER,  D.C.L.  With  520  Illustra- 
tions. In  One  Vol.  (732  pages).  12mo,  cloth $3.00 

MUSIC, 

A  Rudimentary  and  Practical  Treatise  on.     By  C.  C.  SPENCER.     12mo. 

$1.00 
PIANOFORTE, 

The  Art  of  Playing  the.  With  Exercises  and  Lessons.  By  C.  C. 
SPENCER.  12mo,  cloth .60 


INDEX  OF  SUBJECTS. 


Acetylene  Gas,  Gibbs,  42 

Acoustics,  Smith,  35 

Aerial  Navigation,  Walker,  n 

-  Tramways,  Tayler,  a 
Agricultural    Geology,    McCon- 

neU,  50 

-  Note  Book,  McConnell,  52 

—  Surveying,  Scott,  51 

Air  Machinery,  Weisbach,  9,  22 
Algebra,  Haddon,  54 
Alkali  Trade,  Lamas,  42 
Alphabets,  Delamotte,  39 
Alternating    Current    Machines, 

Sheldon  and  Mason,  29 
Animal  Physics,  Lardner,  56 

—  Physiology,  Lardner,  41 
Arches,  Piers,  &c.,  Bland,  32 
Architect's  Guide,  Rogers,  34 
Architectural    Modelling,    Rich- 
ardson, 34 

Architecture,  Ancient,  34 

—  Civil,  Chambers,  34 

—  Design,  Garbett,  34 
Grecian,  Aberdeen,  35 

—  Mechanics  of,  Tarn,  34 

—  Modern,  34 

—  of  Vitruvius,  Gwilt,  35 

—  Orders,  Leeds,  34 

—  Orders  and  Styles,  34 

—  Styles,  Bury,  34 
Arithmetic,  H addon,  54 

—  Young,  54 

—  Equational,  Hipsley,  54 


Armature,  Windings,  Arnold,  29 
Artists'  Pigments,  Standage,  43 
Asbestos,  Jones,  27 
Astronomical  Glossary,  Gore,  40 
Astronomy,  Lardner,  41 
—  Main  and  Lynn,  40 

Barn  Implements,  Scott,  5 1 

Beams,  Flexure  of,  Guy,  18 

Bees,  Samson,  53 

Blasting,  Burgoyne,  19 

Blowpipe,  Ross,  42 

Boiler   and    Factory   Chimneys, 

Wilson,  4 
Boilers,  Armstrong,  5 

Bauer,  20 

Courtney,  3 

-ftfcy.3 

Horner,  4 

Button,  3 

-  ir/faw,  4 

Book-keeping,  Haddon,  54 
Boot  and  Shoe  Making,  L^no,  44 
Brass  Founding,  Graham,  45 
Bread  and  Biscuit  Baker,  ifW/s, 
46 

Breakfast  Dishes,  Allen,  47 
Brewing  and  Malting,    Wright, 

4i 

Brick  and  Tile  Book,  33 
—  Making,  Dobson,  32 
Brick-cutting,  Hammond,  32 
Bricklaying,  Hammond,  32 

57 


INDEX  TO  CATALOGUE. 


Brickwork,  Walker,  32 
Bridges,  Iron,  H umber,  16 
Iron,  Pendred,  16 

—  Oblique,  Buck,  16 

—  Tubular,  Dempsey,  1 7 
Bridges  and  Viaducts,  Campin, 

I7 

British  Mining,  Hunt,  25 
Builders'  Measuring,  Beaton,  33 

—  Quantities,  Beaton,  33 
Building,  a  Book  on,  Beckett,  31 

—  Art  of,  Dobson,  31 

—  Construction,  Allen,  31 

—  Cottage,  Allen,  31 

—  Dwelling   Houses,    Brooks, 

32 

Estates,  Maitland,  31 

Farm,  Scott,  32 

Science  of,  Tarn,  31 

Cabinet-Making,  Bitmead,  37 

Working,  Hasluck,  48 

Calculator,  O'Gorman,  56 
Calculus,  Differential,  Woolhouse, 

55 

Integral,  Cox,  55 

Carpenter's    Guide,    Nicholson, 

Carpentry  and  Joinery,  Tredgold 

and  Tarn,  37 
-  Tredgold,  37 
Cattle,  Sheep,  &c.,  Burn,  50 
Cements,   &c.,  Standage,  47 
Chain  Cables,  Traill,  20 
Chemistry  of  Mining,  Byrom,  26 
Chimneys,  Wilson,  4 
Circular  Work,  Callings,  37 
Civil  Engineering,  Law,  18 
Clock  Jobbing,  Hasluck,  48 
Clocks,     Watches,     and    Bells, 

Beckett,  45 

Coach-Building,  Burgess,  47 
Coal  &  Iron  Industries,  Meade, 
26 

Mining,  Cockin,  26 

Smyth,  26 

Colliery  Manager,  Pamely,  25 
—  Working,  Bulman  and  Red- 
may  ne,  26 


Colouring,  Field   &•»    Davidson, 

39 
Colours    &    Dye  Wares,   Slater, 

42 

Commerce,  Gambaro,  49 
Commercial        Correspondence, 

Baker,  49 
Compound     Interest,     Thoman, 

54 

Concrete,  Sutcliffe,  33 
Confectioner,  Flour,  Wells,  47 
Confectionery,  Wells,  46 
Constructional      Ironwork, 

Campin,  17 
Copper,  Metallurgy  of,  Eissler, 

24 
Cottage  Building,  ^4 //<?«,  31 

—  Gardening,  Hobday,  52 
Cotton      Manufacture,      Lister, 

44 

Cranes,  Glynn,  u 
Creation,  Records  of,  Le  Vaux, 

40 

Curves,  Tables  of,  Beazeley,  15 
Cyanide  Process,  Eissler,  23 

Dairying,  British,  Sheldon,  50 
Dairy,  Pigs,  and  Poultry,  Burn, 

5° 

Dangerous  Goods,  Phillips,  42 
Decoration,  Facey,  38 

House-Painting,    Graining, 

&c.,  38 

—  Imitation    of    Woods    and 
Marbles,  38 

Marble,  Blagrove,  39 


Decorator's  Assistant,  39 

Deep  Level  Mines  of  the  Rand, 

Denny,  22 

Diamond  Drilling,  Denny,  23 
Dictionary       of       Architecture, 

Weale  and  Hunt,  56 

—  Painters,  Daryl,  56 
Direct  Current  Machines,  Sheldon 

and  Mason,  29 
Drainage  of  Lands,  Clark,  14 

-  (Mine),  Michell,  25 
Draining    &  Embanking,  Scott, 


INDEX  TO  CATALOGUE. 


59 


Drawing  Instruments,  Heather, 

55 

-  Rules  on,  Pyne,  34 
Dwelling  Houses,  Brooks,  32 
Dynamic    Electricity,    Atkinson, 

3° 

Dynamo  Construction,  Urquhart, 
29 
•  How  to  Make,  Crofts,  29 

—  Motor     and     Switchboard 
Circuits,  Bowker,  29 

Earthwork,  Graham,  16 

-  Tables,  Broadbent  &•  Cam- 
pin,  1 6 

-  Tables,  Buck,  16 
Earthy  Minerals,  Davies,  24 
Electrical  Calculations,  Atkinson, 

3° 
—  Conductors,  Perrine,  29 

—  Engineering,  Alexander,  28 
Sewell,  28 

—  Pocket  Book,  Kempe,  30 

-  Transmission,  Abbott,  28 
Electricity   Applied   to   Mining, 

Lupton,  Parr,  &*  Perkin,  25,  28 

—  Lardner  and  Foster,  41 

-  Text-Book,  Noad,  30 
Electric  Light  Fitting,  Urquhart, 

3° 

—  Light,  Knight,  30 

—  Light,  Urquhart,  30 

—  Lighting,  Sunnton,  30 

—  Ship-Lighting,  Urquhart,  30 

-  Telegraph,  Lardner,  41 
Electro-Metallurgy,  Wo//,  45 

Plating,  Urquhart,  45 

Plating,  Wotf   and  ^Philip, 

45 

-  Typing,  Urquhart,  45 
Embroiderer's  Design,  Delamotte, 

39 

Engine-Driving    Life,  Reynolds, 

6 
Engineering  Chemistry,  Phillips, 

42 

Drawing,  Maxton,  8 

Estimates,  9 

Engineering  Tools,  Horner,  2 


Engineer's  Assistant,  Templeton, 

8 

—  Companion,  Edu<ards,  8 

-  Field  Book,  Haskoll,  15 

—  Handbook,  Hutton,  5 

-  Pocket-Book,  Clark,? 

—  Reference  Book,  /•Wry,  3 

-  Turning,  Horner,  2 

—  Year  Book,  Kempe,  7 
Engineman's  Companion,  Reyn- 

olds, 7 

Euclid,  Law,  54 
Excavating,  Prelini,  16 
Explosives,  Eissler,  42 

—  Nitro,  Sanjord,  42 

Factory    Accounts,    Garcke    &• 

Fe//5,  49 
Farm  Buildings,  So?//,  32 

—  Engineering,  5co//,  5  1 

—  Management,  Burn,  51 
-Roads,  &c.,  Scott,  51 

Farmer's  Tables,  Francis,  52 
Farming  Economy,  £nr;i,  52 
-  Outlines,  Burn,  51 

—  Small,  Burn,  5  1 
Fertilisers,  &c.,  Dyer,  50 
Field  Fortification,  Knollys,  56 

—  Implements,  5co//,  5  1 
Fields  of  Gt.  Britain,  Clements, 

51 

Fires  &  Fire  Engines,  Young,  1  1 
Flour,  Kick  and  Powles,  46 
Forestry,  Curtis,  36 
Foundations,  &c.,  Dobson,  19 
French  Polishing,  Bitmead,  47 
Fruit  Trees,  Z>w  £r««Y,  53 
Fuel,  Williams  and  Clark,  10 
Fuels,  Phillips,  10 

Garden,  Forcing,  Wood,  52 

—  Receipts,  QMIW,  52 
Gardening,  Good,  Wood,  52 

-  Ladies',  Wood,  53 
-  Multum-in-Parvo, 


Gas  and  Oil  Engines,  Bale, 
-  Engines,  Goodeve,  7 


52 


6o 


INDEX  TO  CATALOGUE. 


Gas   Engineer's    Pocket    Book, 
O'Connor,  42 

—  Fitting,  Black,  47 

—  Producer    Plants,   Mathot, 

6 

-  Works,  Hughes,  18 
Geology,  Historical,  Tate,  27 

—  Physical,  Tate,  27 

—  Tate,  27 
Geometry,  Tarn,  17 

—  Analytical,  Hann,  55 

—  Descriptive,  Heather,  54 

-  Technical,  Sprague,  1 7 

—  of  Compasses,  Byrne,  17 

—  Plane,  Heather,  54 
Girders  (Iron),  Buck,  17 

Glass     Staining,     Gessert     and 

Fromberg,  40 
Gold  Assaying,  Phillips,  23 

—  and  Silver,  Merrill,  23 

—  Metallurgy  of,  Eissler,  23 

—  Prospecting,  Rankin,  23 
Goldsmith's  Handbook,  Gee,   45 

—  and  Silversmith,  Gee,  46 
Grafting    and    Budding,  Ballet, 

53 

Granites,  Harris,  27 
Grazier,  Complete,  Fream,  50 

Hall    Marking    Jewellery,    Gee, 

45 
Handrailing,  Callings,  37 

—  Goldlhorp,  37 

Hay   &  Straw  Measurer,  Steele, 

52 

Health   Officer,   Willoughby,  35 
Heat  (Expansion  by),  Keily,  18 
Heat,  Lardner  and  Loewy,  41 
Heating  by  Hot  Water,   J0w<?5, 

33 
Hints  to  Architects,   Wight-wick 

andGuillaume,  34 
Hoisting  Machinery,   Homer,  2 
Hoisting      &      Conveying     Ma- 
chinery, Zimmer,  2 
Horology,  Saunier,  44 
Horticulture,  Newsham,  52 
House  Decoration,  Facey,  38 
Painting,  Davidson,  39 


Hydraulic  Manual,  Jackson,  13 

—  Engineering,  Marks,  13 
-  Tables,  Neville,  13 

Hydrostatics,  Lardner,  41 

Illumination,  Delamotte,  39 
India  Rubber,  Johnson,  43,  53 
Inflammable  Gas,  Clowes,  26 
Iron  and  Steel,  Hoare,  8 
Iron,  Metallurgy  of,  Bauerman, 
25 

—  Ores,  Kendall,  25 

—  Plate       Weight       Tables, 
Burlinson  and  Simpson,  49 

Irrigation,  Mawson,  n 

—  and  Water    Supply,    Scott, 


Jeweller's  Assistant,  Gee,  45 
Joints  (Builders'),  Christy,  37 

Key  to  Haddon's  Algebra,  54 

—  to  Young's  Arithmetic,  54 
Kitchen  Gardening,  Glenny,  52 

Land,  Ready  Reckoner,  Arntan, 

52 

-  (Reclamation    of),    Beaze- 
ley,  12 

Landed  Estates,  Burn,  51 
Lathe  Work,  Hasluck,  9 
Laundry,  Management,  47 
Lead     (Argentiferous),    Eissler, 

24 

Leather  Manufacture,  Watt,  44 
Letter  Painting,  Badenoch,  39 
Levelling,  Simms,  15 
Light,  Tarn,  35 
Light  Railways,  Calthrop,  n 
Lightning   Conductors,  Hedges, 

32 

Limes,  Cements,  Burnell,  33 
Locks,  Tomlinson,  47 
Locomotive  Engine,  Stretton,  6 

-  Engine,  Weatherburn,  6 

—  Engine  Driving,  Reynolds,  6 

-  Engineer,  Reynolds,  6 

-  Engines,  Dempsey,  6 


INDEX  TO  CATALOGUE. 


61 


Logarithms,  Law,  53 

Machine  Shop  Tools,  2 
Machinery,  Details,  Campin,  9 
Marble     Decoration,     Bla  grove, 

39 

Marine     Engineering,      Brewer, 
20 

—  Engineer,  Wannan,  20 

—  Engineer's    Pocket    Book, 
Wannan,  20 

Marine     Engines      &     Boilers, 
Bauer,  Donkin  and  Robertson, 

W 

Engines,  Murray,  20 

Market  Gardening,  Shaw,  52 
Masonry,  Purchase,  32 
and    Stone-Cutting,    Dob- 
son,  32 

—  Dams,  Courtney,  13 
Masting  and  Rigging,  Kipping, 

21 

Materials,  Campin,  18 
(Strength  of),  Barlow,  iB 

—  Handling  of,  Zimmer,  i 
Mathematical    Insts.,    Heather, 

Heather  6r»  ]%almisley,  55 

Tables,   Law  and    Young, 

22>  53 

Mathematics,  Campin,  53 
Measures,  Weights,    &c.,  Wool- 
house,  56 

Measuring      Builders'       Work, 
Dobson  and  Tarn,  33 

-  Timber,  &c.,  Horton,  33 
Meat  Production,  Ewart,  50 
Mechanical    Dentistry,  Hunter, 

45 

—  Engineering,  Campin,  9 

—  Handling      of      Material, 
Zimmer,  i 

-  Terms,  Lockwood,  8 
Mechanics,  Hughes,  9 

—  Lardner  and  Loewy,  40 

—  Tomlinson,  10 

—  of   Air   Machinery,    Weis- 
bach,  9,  22 

(Tables  for),  Smith,  8 


Mechanics'     Companion,    Tem- 
pleton  and  Hutton,  8 

-  Workshop,  Hasluck,  48 
Mechanism,  Baker,  10 
Mensuration  &  Gauging,  Afant, 

4i 
and      Measuring,      Baker, 

i? 

Metal  Turning,  Hasluck,  48 
Metalliferous  Minerals,  Davits, 

24 
Mining  Machinery,  Davits, 

22 

Metric  Tables,  Dowling,  49 
Metrology,  Jackson,  49 
Microscope,  Van  Heurck,  40 
Milk,  Cheese,  &c.,  Oliver,  50 
Milling  Machines,  Horner,  2 
Mine  Drainage,  Michell,  25 
Mines  of  the  Rand,  Denny,  22 
Mineral  Surveyor,  Lintern,  27 
Mineralogy,  Ramsay,  27 
Miners'    Handbook,    Milne,    25 

-  Pocket  Book,  Power,  24 
Mining,  British,  Hunt,  24 
Calculations,   OJDonahue, 

26 

Chemistry  of,  Byrom,  26 

Students,  Notes  for,  Meri- 

vale,  26 
—  Tools,  Morgans,  27 

and     Quarrying,     Collins, 

27 

Model  Engineer,  Hasluck,  48 
Mollusca,  Woodward,  40 
Motor  Cars,  Tayler,  n,  47 

Vehicles,  Tayler,  1 1 

Museum    of   Science    and    Art, 

Lardner,  41 
Music,  Spencer,  56 

Natural  Philosophy,  Tomlinson, 

56 

for  Schools,  Lardner, 

4i 
Naval  Architect's  Pocket  Book, 

Mackrow,  20 

—  Architecture,  Peake,  2 1 
Navigation,  Young,  22 


62 


INDEX  TO  CATALOGUE. 


Navigation,      Greenwood      and 
Rosser,  21 

—  Practical,  21 

Oil  Fields  of  Russia,  Thompson, 
22,  41 

Oils,  Analysis  of,  Wright,  41 
Optical    Instruments,    Heather, 

55 

Optics,  Lardner  &>  Harding,  41 
Organ  Building,  Dickson,  47 

Packing  Case  Tables,  Richard- 

son, 38 

Painting,  Qullick  &  Timbs,  40 
Paper,  Parkinson,  43 

—  Making,  Clapperton,  43 

-  Watt,  43 

Pastrycook's  Guide,  Wells,  46 
Patents,  Hardingham,  56 
Pattern  Making,  Hasluck,  48 
--  Horner,  8 
Perspective,  Ferguson,  33 
34 


Pianoforte,  Spencer,  56 
Pioneer    Engineering,     Dobson, 

15 

Plastering,  Kemp,  33 
Plating    &   Boilermaking,  JETor- 

wer,  4 

Plumbing,  Buchan,  33 
Pneumatics,  Tomlinson,  19 
Pocketbook,    Agriculturist's, 

Francis,  55 

—  McConnell,  52 

—  Builder's,  Beaton,  33 

—  Electrical,  Kempe,  30 

—  Engineer's,  Clark,  7 
--  Edwards,  8 

—  Fletcher,  8 

-  -  Hasluck,  9 
--  Kempe,  7 
--  Smith,  8 
--  Templeton,  8 

-  Engineman's,  Reynolds,  6 

-  Gas  Engineer's,  O'Connor, 

43 
—  Health  Officer's,  Willoughby, 

35 


Pocketbook,  Marine  Engineer  s, 

Mackrow,  20 
Wannan,  20 

—  of          Mensuration       and 
Measuring,  Mant,  41 

—  Miner's,  Milne,  25 
—  Power,  24 

—  Mining      Prospecto  r's, 
Anderson,  24 

Merritt,  24 

Rankin,  23 

of  Refrigeration,  Tayler, 

10 
Portable  Engine,  Wansbrough, 

Portland    Cement,    Faija    and 

Butler,  33 
Portuguese    Dictionary,    Elwes, 

56 

—  Grammar,  Elwes,  56 
Producer-Gas  Plants,  Mathot,  6 
Prospector's  Handbook,  Ander- 
son, 24 

Pumps  and  Pumping,  ZJa/tf,  10 

Quantities  (Builders'),  Beaton,  33 

Railway  Brakes,  Reynolds,  6 

—  Working,  Stretton,  19 
Reclamation  of  Land,  Beazeley, 

12 
Refrigerating  Machinery,  TVy- 

/er,  ii 
Refrigeration,  Tayler,  10 

—  (Pocket  Book),  TVy/er,  n 
River  Bars,  Mann,  14 
Roads  and  Streets,  Law,  16 
Roof  Carpentry,  Callings,  37 
Roofs,    Construction    of,    Tarn, 
.  18 
Rothamsted  Experiments, 

r/^r,  50 

Sailmaking,  Kipping,  21 
Sadler,  21 


Sanitary  Work,  Slagg,  36 
Savouries    and    Sweets,    Allen, 
47 


I&DEX  TO  CATALOGUE. 


Saw  Mills,  Bale,  36 
Screw  Threads,  Hasluck,  9 
Sea  Terms,  Pirrie,  21 
Sewage,  Irrigation,  Burn,  52 

—  Purification,  Barunse,  36 
Sewing    Machinery,     Urquhart, 

47 

Sheep  (The),  Spooner,  50 
Sheet-Metal  Work,  Cran*,  46 
-  Work,   Warn    &•   Horner, 

46 

Shoring,  Blagrove,  32 
Ship  Building,  Sommerfeldt,   21 

—  German,  Felskowski,  21 
Ships  and  Boats,  Bland,  21 
Silver,  Metallurgy  of,  Eissler,  24 
Silversmith's  Handbook,  Gtftf,  45 
Slate  Quarrying,  Davits,  27 
Slide  Rule,  /foare,  53 

Smithy  and  Forge,  Crane,  9 
Soap  Making,  Watt,  44 
Soils,  Burn,  50 
Spanish  Dictionary,  FJwes,  56 

Grammar,  FJwes,  56 

Specifications,  Bartholomew,  31 

—  in  Detail,  Macey,  31 
Star  Groups,  Gore,  40 
Statics,  Graham,  17 

and  Dynamics,  Baker,  55 

Stationary       Engine       Driving, 
Reynolds,  6 

—  Steam  Engines,  Hurst,  6 
Steam  and  Machinery  Manage- 
ment, Bale,  7 

and  Steam  Engine,  Clark, 

10 

Steam  Boiler  Construction,  Hut- 
ton,  3 

—  Boilers,  Armstrong,  5 

—  Wilson,  4 

Engine,  Baker,  6  % 

—  Goodeve,  5 

Haeder  and  Powles,  5 

Lardner,  6 

—  Safe  Use  of,  7 

Stone       Working       Machinery, 

Bale,  ii 

Strains  in  Girders,  Humber,  17 
on  Ironwork,  Shields,  17 


Submarine    Telegraphs,   Bright, 

3° 
Superficial   Mcasuremnt, 

Hawkings,  38 

Survey  Practice,  Jackson,  14 
Surveying,  Baker  and  Dixon,  14 

Frame  and  Warren,  15 

Instruments,  Heatlier,  55 

Land  &  Marine,  HaskoU,  14 

—  Subterraneous,  Fenwick,  27 

—  £/*#/,  14 

—  Whitelaw,  14 

with    Tacheometer,    Ken- 
nedy, 14 

Tea  Machinery,  Tayler,  46 
Technical  Guide,  3eaton,  33 

Terms,  FleUher,  8 

Timber  Importer,  Grandy,  37 

Merchant,  Dowsing,  37 

Kichardson,  38 

Toothed  Gearing,  Horner,  9 
Tramways,  Clark,  16 
Transmission      by      Electricity, 

Atkinson,  29 

Traverse  Tables,  Lintern,  27 
Tree  Planter,  W<W,  53 

—  Pruner,  WoW,  53 
Trigonometry,  Plane,  Hann,  55 

—  Spherical,  Hann,  55 
Trusses,  Griffiths,  18 
Tunnelling,  Prelini  and  Hill,  15 

Simms  and  Clark,  15 

Tunnel  Shafts,  £«<;£,  16 
Turning,  Engineers',  Horner,  2 

Lathe,  Hasluck,  9 

-  Metal,  Hasluck,  48 

—  Wood,  Hasluck,  48 

Ventilation  of  Buildings,  Buchan, 
36 

Villa  Architecture,  Wickes,  34 
Visible  Universe,  Gore,  40 
Vitruvius'    Architecture,    Gwilt, 

Watch  Jobbing,  Hasluck,  48 

—  Maker,  Saunier,  44 

—  Repairing,  Garrard,  44 
Watches,  History  of,  Kendal,  45 


INDEX  TO  CATALOGUE. 


Water  Purification,  Rideal,  35 
-  Engineering,  Slagg,  13,  35 

Power  of,  Glynn,  13 

—  Supply,  Humber,  12,  35 

Greenwell  and  Curry, 

12,  35 

Supply  of  Towns,  Burton, 

I2>  35 

Waterworks,  Hughes,  13 
Well-Sinking,  Swindell,  13 


Wireless  Telegraphy,  Sewall,  29 
Wood  Carving  for  Amateurs,  40 
—  Engraving,  Brown,  47 

—  Turning,  Hasluck,  48 
Woods  and  Marbles,   Imitation 

of,  Van  der  Burg,  38 
Woodworking,  Hasluck,  48 

—  Machinery,  Bale,  36 
Workshop  Practice,  Winton,  9 
Works'  Manager,  Hutton,  3 


(/, 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


29  1935 


Di 


17Mar'5lAW 
LTD 


REC'D  LD 


LD  21-100m-8,'34 


~?fi 


